Contents
2006
Volume: 26 Issue 5
31 Article(s)
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Atmospheric Optics and Oceanic Optics
Measurement of Self-Broadening and N2 Broadening Coefficients of Water Vagor Molecule Near 1.31 μm
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
High-resolution absorption spectroscopy of water vapor molecule was recorded by narrow linewidth diode laser and a kilometer order White cell, minimum detectable line strength is 10-27 cm-1/(molecule·cm-2. The line strength, the self broadening and N2 broadening coefficients of water vapor molecule in the 7599～761High-resolution absorption spectroscopy of water vapor molecule was recorded by narrow linewidth diode laser and a kilometer order White cell, minimum detectable line strength is 10-27 cm-1/(molecule·cm-2. The line strength, the self broadening and N2 broadening coefficients of water vapor molecule in the 7599～7616 cm-1 region were accurately determined. The measured line parameters are compared with HITRAN96 and HITRAN2004 databases, some differences exist. The measured line parameters consist with HITRAN96 database, but there exists large difference with HITRAN2004 database. Seven new lines unlisted in HITRAN96 data base were observed, five of them were confirmed in HITRAN2004 data base. Another two lines listed in HITRAN96 data base were observed, but unlisted in HITRAN2004 data base..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 641 (2006)
Simulation and Computation of Bubbles Volume Scattering Function in Water
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
An equation for calculating relation of the incident angle and the scattering intensity from a large scale air bubble in water is derived based on the principle of geometrical optics. By neglecting the attenuation factor G, the formula is much simpler than the Davis model. One application of the model is to calculate tAn equation for calculating relation of the incident angle and the scattering intensity from a large scale air bubble in water is derived based on the principle of geometrical optics. By neglecting the attenuation factor G, the formula is much simpler than the Davis model. One application of the model is to calculate the angular distribution of the scattering light by a single air bubble. The volume scattering function is simulated with the collimated light incident on the air bubble. It is found that the forward scattering is far greater than the backward scattering. As long as the bubble radius is much larger than the wavelength of light, the angular distribution of the scattering light is not influenced by the change of bubble radius. However, the increase of relative refraction index weakens the forward scattering while strengthens the backward scattering on the bubble surface..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 647 (2006)
Diffraction and Gratings
Rigorous Vector Analysis of Multi-Layer Dielectric Film Pulse Compression Gratings
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The multi-layer film pulse compression grating used in expanding and compressing laser pulse is composed of multi-layer dielectric film with high reflectance and relief gratings on its top. Based on the designed multi-layer film with high reflectance, the distribution of diffraction field of multi-layer pulse compressiThe multi-layer film pulse compression grating used in expanding and compressing laser pulse is composed of multi-layer dielectric film with high reflectance and relief gratings on its top. Based on the designed multi-layer film with high reflectance, the distribution of diffraction field of multi-layer pulse compression gratings is analyzed by Fourier modal theory and the expression of its diffraction efficiency is given on the condition of transverse electric field incidence at Littrow angle. With the merit function of the first order diffraction efficiency of multi-layer dielectric film gratings, the grating parameters, with which the first order diffraction efficiency is higher than 0.95, are discussed when materials of top layer are HfO2 and SiO2, respectively. The results show that a larger grating parameter range is got with HfO2 than SiO2. Optimized structure parameters of gratings are given and errors of grating fabrication and tolerances in use are discussed, which gives some theoretical guiding to the fabrication technics and applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 652 (2006)
Image Processing
Research on Image Fusion Based on the Second Generation Curvelet Transform
[in Chinese], [in Chinese], and [in Chinese]
Curvelet, as a new multiscale analysis algorithm, is more appropriate for the analysis of the image edges such as curve and line characteristics than wavelet, and it has better approximation precision and sparsity description. When the curvelet transform is introduced to image fusion, the characteristics of original imCurvelet, as a new multiscale analysis algorithm, is more appropriate for the analysis of the image edges such as curve and line characteristics than wavelet, and it has better approximation precision and sparsity description. When the curvelet transform is introduced to image fusion, the characteristics of original images are taken better and more information for fusion is obtained. The proposal of the second generation curvelet theory makes it under-stood and implemented more easily. Then the second generation curvelet transform based image fusion method is proposed. Firstly, the source images are decomposed using curvelet transform, then the curvelet coefficients are fused with the fusion regular in the corresponding scales, and finally the fused coefficients are reconstructed to obtain fusion results. Multi-focus images are taken as experimental data, mean square error, difference coefficient, correlation coefficient are used to evaluate the results, and comparison with results based on wavelet transform is also carried out . The results show that when decomposition level is 2, this method gets fusion result of similar quality with wavelet, but for other decomposition levels this method gets much better fusion results than wavelet..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 657 (2006)
Novel Phase Unwrapping Algorithm for Digital Speckle Pattern Interferometry
[in Chinese], and [in Chinese]
Novel phase unwrapping algorithm for digital speckle pattern interferometry (DSPI) is proposed, which is mainly for the complex and discontinuous structure under the illumination of laser, the discontinuous area of phase is detected and identified through the subtraction of two speckle pattern interferograms,with opposNovel phase unwrapping algorithm for digital speckle pattern interferometry (DSPI) is proposed, which is mainly for the complex and discontinuous structure under the illumination of laser, the discontinuous area of phase is detected and identified through the subtraction of two speckle pattern interferograms,with opposite optical phases. Then improved unwrapping process based on the traditional line scan method is conducted in the region where phase is available, and the phase unrapping in the whole available area came out accurately and promptly. This algorithm is more efficient and simpler compared with others reported in the literature, and it can avoid the large phase discontinuous area effectively and conveniently. This novel phase unwrapping algorithm makes quantitative analysis in the actual engineering, such as distortion and vibration using DSPI very convenient..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 663 (2006)
Instrumentation, Measurement and Metrology
On-Site Coma Measurement Technique Base on Linewidth Asymmetry of the Aerial Image
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In high numerical aperture and low technic factor lithography process, degradation of the image quality because of the coma aberration in the projection lens has become a serious problem. Fast and accurate on-site measurement of coma aberration is required. A novel on-site coma measurement technique based on linewidth In high numerical aperture and low technic factor lithography process, degradation of the image quality because of the coma aberration in the projection lens has become a serious problem. Fast and accurate on-site measurement of coma aberration is required. A novel on-site coma measurement technique based on linewidth asymmetry of the aerial image is proposed. Compared with the resist-based coma measurement techniques, the technique based on the aerial image possess the advantage of time-saving. The simulation results of PROLITH show that the measurement accuracy of the technique is better than 1.4 nm. The accuracy increases approximately 30 percent and 1/3 measuring time is saved compared with the TAMIS technique. Using the technique, the coma of the projection lens on PAS5500 scanner of ASML is measured. The experiment shows that the reproducibility of the coma measurement is better than 1.2 nm, and this technique can meet the requirement of the high-accuracy coma measurement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 673 (2006)
New Technique for Aberration In-Situ Measurement of a Lithographic Projection System
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new technique for measuring the aberrations of a lithographic projection system in situ is proposed, in which the basic theory used to measure the spherical aberration, coma and astigmatism of the projection system with special measurement mark is analyzed in detail, and the method to calculated the image displacemenA new technique for measuring the aberrations of a lithographic projection system in situ is proposed, in which the basic theory used to measure the spherical aberration, coma and astigmatism of the projection system with special measurement mark is analyzed in detail, and the method to calculated the image displacement caused by aberration through aligned position coordinate is presented. Through experiments, the aberration parameters, such as spherical aberration, coma and astigmatism of the projection system are obtained with high accuracy by the technique. Taking into account of the influences of process factors, e.g. resist process, on the image displacement induced by aberration, the new technique avoids the dependence of coma in-situ measurement based on wafer exposure on the image parameters, such as defocus and image tilt..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 679 (2006)
Method and Precision Analysis for Measuring Retardation of Infrared Waveplate
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A new method for measuring the retardation of waveplates in the infrared spectral region is derived by analyzing the light intensity variation with the azimuth angle. The phase retardations of waveplate are determined through reading out the maximum and minimum of light intensities and simple calculation. Based on thisA new method for measuring the retardation of waveplates in the infrared spectral region is derived by analyzing the light intensity variation with the azimuth angle. The phase retardations of waveplate are determined through reading out the maximum and minimum of light intensities and simple calculation. Based on this method, an instrument is set up to measure the retardations of the waveplates in the infrared range. With less devices, easy operation and sound repetition, measurement results with high precision are obtained. The effects on the measurement precision of the different sources, such as light source, polarizer and detector, etc., have been analyzed. It is found that the instrumental accuracy is related to the waveplate retardation, and their relation is plotted. From the plot it is found that the measurement precision is within 1% when the retardations of waveplates are more than 40°. The relative errors are measured to be 0.2% and 0.01% for the conventional quarter and half waveplates, respectively. The measurement precision of the system is almost constant in the visible and near-infrared range..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 685 (2006)
Lasers and Laser Optics
Study of a Nd∶YAG Laser with Voltage-Decreased Electro-Optical Q-Switch of Optical Activity Crystal La3Ga5SiO14
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The interaction between the optical rotation and electro-optic effect has been studied. The express equation of the emitted light intensity under the interaction of the optical rotation and electro-optic effect is given, which is I=1-4B2(Asin2ω-Ccos2ω)2. According to the theoretical equation, the shutdown voltage and pThe interaction between the optical rotation and electro-optic effect has been studied. The express equation of the emitted light intensity under the interaction of the optical rotation and electro-optic effect is given, which is I=1-4B2(Asin2ω-Ccos2ω)2. According to the theoretical equation, the shutdown voltage and polarization plane angle for a Q-switch of La3Ga5SiO14 (LGS) crystal with the size of 8 mm×8 mm×25 mm for the wavelength of 1064 nm are calculated to be 4995 V and 27.3°, which is validated by the experiment of a voltage-decreased electro-optical Q-switched Nd∶YAG laser. The experimental results are in basic agreement with the calculation values. The output energy of 361 mJ and the pulse width of 7.8 ns are obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 689 (2006)
Output Properties of External Resonator SrWO4 Raman Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The output properties of an external resonator SrWO4 Raman laser pumped by nanosecond pulses are studied. An actively Q-switched Nd∶YAG laser is used as the pumping source, with pulse width of 11.7 ns and energy of 80 mJ. The Raman laser cavity is a flat-flat one. Four output couplers with different reflectivities for The output properties of an external resonator SrWO4 Raman laser pumped by nanosecond pulses are studied. An actively Q-switched Nd∶YAG laser is used as the pumping source, with pulse width of 11.7 ns and energy of 80 mJ. The Raman laser cavity is a flat-flat one. Four output couplers with different reflectivities for the first- and second-Stokes wavelengths are used in the experiment. The relations between the output energy and pumping energy are measured, and the relations between the conversion efficiency and pumping energy are calculated. When the output coupler reflectivity for the first-Stokes wavelength is 39.9％, the obtained maximum output energy and conversion efficiency of the first-Stokes pulses are 23.9 mJ and 36.2%, respectively. When the output coupler reflectivities for the first and the second-Stokes wavelengths are 80.5％ and 12.4％, respectively, the obtained maximum output energy and conversion efficiency of the second-Stokes pulses are 16.4 mJ and 25.4%, respectively. The pulse widths of the typical first and second-Stokes pulses are 6.1 ns and 5.8 ns, respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 693 (2006)
Machine Vision
Calibration Method with Separation Pattern of a Single-Camera Based on Difference Coordinates
[in Chinese], [in Chinese], and [in Chinese]
The difference calibration and separation patterns are used to calibrate a single-camera with high precision. Several separation calibration patterns with small size are put on the object plane of the camera. Each pattern has some spot array with high precision. Gaussian curved-surface fitting method is used to get theThe difference calibration and separation patterns are used to calibrate a single-camera with high precision. Several separation calibration patterns with small size are put on the object plane of the camera. Each pattern has some spot array with high precision. Gaussian curved-surface fitting method is used to get the position of spot on the CCD image plane, and the stability (RMS) of measurement result of the spot position is 1 μm (about 0.0053 CCD pixel). The object plane difference coordinates of the reference points on the same calibration pattern are used to calibrate the camera. The mapping relationship between the object plane and the image plane is established with the biquadratic curved-surface fitting method. There is not need for the distance between the patterns. The integer pattern with large dimension is replaced by the several small difference patterns. The difficulty to manufacture the large pattern is avoided. When the error of the relative angle between the patterns is less than 60″. The experiment results show that the calibrated mean value of residual error is 4.8 μm (about 0.028 CCD pixels)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 697 (2006)
Research on Signal Processing Method of the Infrared Sensor Skin of New Robot
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The robotics infrared sensor skin is a new outward sensing system which has the characteristics of abundant information, high performance on real-time processing and non-contact measurement for its environment. The infrared sensor skin is widely used in the multi-joint robot system for real-time obstacle avoidance. HowThe robotics infrared sensor skin is a new outward sensing system which has the characteristics of abundant information, high performance on real-time processing and non-contact measurement for its environment. The infrared sensor skin is widely used in the multi-joint robot system for real-time obstacle avoidance. However, the output of mini-type infrared sensors in sensor skin is subjected to noise disturbances caused by visible light, electrical source with its work frequency and fluorescent lamp etc. So, it is very difficult for the traditional analog circuit to meet the system's demand of real-time and veracity. In order to improve the systemic performance, a kind of all-digital signal processing technique based on the digital signal process (DSP) is presented. Signal processing is implemented by using fast Fourier transform (FFT) method. By analyzing the error caused by the FFT method, error compensation is realized by using Hanning window. The results of simulations and experiments show that this technique can reduce the effect of noises and provide accurate and real-time environmental information by using the infrared sensor skin..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 702 (2006)
Materials
Blue Shift of Luminescence of Cl- Ions-Decorated Ce3+-Doped Silica
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A Ce3+-doped nanoscale SiO2 material was prepared by sol-gel method through adding Ce(NO3)3 and the samples were decorated by Cl- at different temperatures to study the effect of Cl- decoration on the luminescent properties of Ce3+ in SiO2. The components and luminescent properties of Ce3+ doped SiO2 after treatment weA Ce3+-doped nanoscale SiO2 material was prepared by sol-gel method through adding Ce(NO3)3 and the samples were decorated by Cl- at different temperatures to study the effect of Cl- decoration on the luminescent properties of Ce3+ in SiO2. The components and luminescent properties of Ce3+ doped SiO2 after treatment were studied by X-ray photoelectron spectra, absorption pattern and fluorescence spectra. The measurement of luminescence showed that the Cl- decoration not only enhanced the intensity of the luminescence of Ce3+ doped SiO2 but also shifted the luminescent band to the short wavelength: the wavelength of emission shifted from 445 nm to 390 nm and the excitation from 326 nm to about 290 nm, and this shift was reversible. When the samples were retreated in the air after Cl- decoration, the intensity and wavelength of the photoluminescence resumed to the original value before Cl- decoration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 707 (2006)
Structure, Thermal Properties and Spectral Properties of Tm3+-Doped Fluorophosphate Glasses
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Fluorophosphate glasses with various Al(PO3)3 content were prepared, and their structure, thermal properties and spectral properties were studied. For these glasses, with the increment of Al(PO3)3 content, the density decreased while the refractive index increases, and transition temperature, the onset and maximum of tFluorophosphate glasses with various Al(PO3)3 content were prepared, and their structure, thermal properties and spectral properties were studied. For these glasses, with the increment of Al(PO3)3 content, the density decreased while the refractive index increases, and transition temperature, the onset and maximum of the crystallization peak temperature and melt temperature increased which were suggested by differential scanning calorimetry. These glasses exhibited the best resistance against crystallization with 7%～9% mole concentration Al(PO3)3 content. Normalized Raman spectrums were used to analyze structure and phonon status. For these glasses the increment of Al(PO3)3 content did not affect phonon energy but resulted in the augment of phonon density. Absorption spectrums were measured. 3H6→3F4 exhibited absorption at L band of the third communication window. Compared with the Tm3+ excited states in other glass system, 3F4 energy level of Tm3+ in these glasses was slightly higher and 3H4 energy level was slightly lower, so it could be predicted that emission band of 3H4→3F4 transition was similar to the amplified band of the gain-shift Tm3+ doped fiber amplifier with a relatively long wavelength. Analyses with Judd-Ofelt theory suggested with the increment of Al(PO3)3 content, phenomenological intensity parameter Ω2 increased, Ω6 varied little, and the radiative lifetime of Tm3+ excited states decreased..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 713 (2006)
Microscopy
Model Design and Parameter Optimization of Stimulated Emission Depletion Fluorescence Microscopy
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The imaging technology of stimulated emission depletion (STED) fluorescence microscopy utilizes the nonlinear relationship between the fluorescence saturation and the excited state stimulated depletion. It implements 3D imaging and breaks the diffraction barrier of the far-field light microscopy by restricting depetionThe imaging technology of stimulated emission depletion (STED) fluorescence microscopy utilizes the nonlinear relationship between the fluorescence saturation and the excited state stimulated depletion. It implements 3D imaging and breaks the diffraction barrier of the far-field light microscopy by restricting depetion zone at a sub-diffraction spot. A model on the revision of the particle velocity equations was found to depict the temporal characteristics of the energy level population probability of fluorescent prob, and the oriterion called time verage depletion efficiency was defined. Gaussian function was used to simulate the two incident laser pulse, and the relationship between the depletion efficiency and the parameters, such as intensity, duration, delay time of both laser pulses, was obtained repsectively by numerical simulation, and the optimal value of these parameters was gained to improve the depletion efficiency is obtained. It is an effective approach to advance the system resolution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 720 (2006)
Optical Design and Fabrication
Dynamic Gaussian Model of Linewidth in Defocus Writing
[in Chinese]
For improving efficiency in fabrication of multi-linewidth integrated optical device, a new fabrication method based on defocus laser writing, namely, a method that the laser does not focus on the surface of photoresist during fabrication, was proposed, and the corresponding mathematical model of linewidth was set up, For improving efficiency in fabrication of multi-linewidth integrated optical device, a new fabrication method based on defocus laser writing, namely, a method that the laser does not focus on the surface of photoresist during fabrication, was proposed, and the corresponding mathematical model of linewidth was set up, too. This model firstly supposes that the transformed laser beam through objective lens keeps Gaussian energy contribution in arbitrary defocus plane, then describes the influence of laser spot outline on exposure energy contribution during laser dynamic scanning. The model is named “dynamic Gaussian model”, which is correlative with light power, defocus amount, scanning velocity of laser beam, exposure energy threshold of photoresist and other fabrication parameters. The verification was carried out in self-developed polar laser pattern generator. It shows that the dynamic Gaussian model is in better agreement with the experimental result and is much better than the static Gaussian model,which ignores the movement of laser spot..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 726 (2006)
Optical Assessment of a Projection Lens Design for Head-Mounted Projective Displays in Visual Space
[in Chinese], and [in Chinese]
A detailed assessment including the assessment procedure and the result in visual space of a projection lens design for head-mounted projective displays is presented. The influences of the focal length and the pupil size of the eye on the modulated transfer function (MTF) are sufficiently considered. The formulae to coA detailed assessment including the assessment procedure and the result in visual space of a projection lens design for head-mounted projective displays is presented. The influences of the focal length and the pupil size of the eye on the modulated transfer function (MTF) are sufficiently considered. The formulae to compute the loss in resolution due to accommodation shifts and astigmatism are given. The results show that for a 3 mm pupil size, the MTF is 0.55 at 0.5 cycles/(′), matching the visual acuity of the human visual system (1′). When the eyes gaze at the center of the projected image, the accommodation shifts of points in the full field of view are less than 0.35D. And the loss in resolution due to accommodation shifts is less than 3.5′. The maximum loss in resolution due to astigmatism is only 1.1′. The maximum value of the lateral color and secondary color are only 0.57′ and 0.17′, less than the visual acuity of the human visual system. The results demonstrate that the lens can fulfill the usability in head-mounted projective displays. That technique can be applied to all the HMDs..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 730 (2006)
Development of Visible-Light Optical Simulator Based on Liquid Crystal on Silicon Technology
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
To offer the true to nature target-background images used in the simulation system for homing weapons, a visual-light optical target simulator based on the liquid crystal on silicon (LCOS) technology is established. The typical output images and measurement method and data of the optical parameter are presented. It is To offer the true to nature target-background images used in the simulation system for homing weapons, a visual-light optical target simulator based on the liquid crystal on silicon (LCOS) technology is established. The typical output images and measurement method and data of the optical parameter are presented. It is proved that the simulator has more appropriate luminance, higher contrast and better uniformity than other conventional ones. Compared with the cathode ray tube (CRT) technology, it avoids the flicker problem and offers steady video outputs, which can greatly improve the seeker's ability of capturing the goal. So the LCOS technology is an ideal choice for optical simulators. Besides, the calculation method of illumination system based on the double fly eye lens is provided and simple results are gained which can also be used in other illumination systems of projection..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 736 (2006)
Optical Devices
Mechanical Interleaving Assembly of TDICCD Focal Plane
[in Chinese], and [in Chinese]
There is a developing trend of wide field of view and high resolution for the remote sensor, and the imaging focal plane is longer and longer. TDICCD has been widely used in the field of the remote sensor with its good imaging performance, and it is more and more important to achieve large focal plane for TDICCD assembThere is a developing trend of wide field of view and high resolution for the remote sensor, and the imaging focal plane is longer and longer. TDICCD has been widely used in the field of the remote sensor with its good imaging performance, and it is more and more important to achieve large focal plane for TDICCD assembly. The conventional optical assembly length is limited by glass material and glass glue, moreover it introduces chromatic aberration, and the directive assembly will descend the imaging quality. A new assembly method called mechanical interleaving assembly of TDICCD focal plane, which eliminates the above defects, is put forward. Using mechanical tangent-screws adjusting method, the assembly of two TDICCDs staggerd in space is finished on the apparatus which is composed of a long work-distance magnifying microscope, a fine collimating reticle, a negative-pressure adsorption air float guide and precision slidway. The assembly focal plane length reaches 400 mm and the measuring error is not greater than 2.9 μm. The relationship of positions of TDICCDs is ensured, and the image displacement disposed method of electronic abutting joint zero clearance imaging picture is achieved..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 740 (2006)
Arrays of Narrow Bandpass Filters Fabricated by Combinatorial Etching Technique
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The basic mechanism and fabrication processes of the combinatorial etching technique have been introduced. It is a high-efficiency technique for the integration of narrow bandpass filters (NBPFs). A filter array integrated with 2N NBPFs can be fabricated with only N times of etching processes, and the technique can be The basic mechanism and fabrication processes of the combinatorial etching technique have been introduced. It is a high-efficiency technique for the integration of narrow bandpass filters (NBPFs). A filter array integrated with 2N NBPFs can be fabricated with only N times of etching processes, and the technique can be applied in different wavelength regions. The experimental results of the array integrated with 32 filters in the visible-NIR and the array integrated with 16 filters in the MIR have been demonstrated. The pass-bands of the former NBPFs distribute linearly in the range of 774.7～814.2 nm. All the filters' full widths at half maximum (FWHM) are very narrow and less than 1.5 nm, corresponding to δλ/λ of each filter less than 0.2%. The narrowest FWHM of the integrated filters comes to 0.8 nm with δλ/λ of 0.1% at the wavelength of 794.3 nm. The transmittances of the pass-bands are between 21.2% and 32.4%. Most of them are near 30%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 746 (2006)
OPTOELECTRONICS
Research on Reflection Spectrum of Al0.5Ga0.5As-AlAs Distributed Bragg Reflector at Different Incidence Angles
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The reflection spectra of Al0.5Ga0.5As-AlAs distributed Bragg reflector (DBR) at different incident angle are calculated by transfer matrix method. The reflection spectra curve of p-polarized and s-polarized plane waves vary with a ‘V’ shape with the rise of the incident angle and the lowest reflectivity is at 49.8The reflection spectra of Al0.5Ga0.5As-AlAs distributed Bragg reflector (DBR) at different incident angle are calculated by transfer matrix method. The reflection spectra curve of p-polarized and s-polarized plane waves vary with a ‘V’ shape with the rise of the incident angle and the lowest reflectivity is at 49.8°. The reflection spectra of different incident media [air and Al0.7Ga0.3)0.5In0.5P] are greatly different at different incident angles. The change of the reflection spectrum from air to DBR is small, the reflectivity is 88.13% at incident angle 0° as well as 84.98% at 45°, and the peak wavelength of reflection spectrum is blue-shifted about 10 nm. But the change of reflection spectrum of from (Al0.7Ga0.3)0.5In0.5P to DBR is great, the reflectivity decreases over 45% and the peak wavelength is blue-shifted over 127 nm from incident angle 0°to 45°.In order to reduce the changes, a new multi-wavelength DBR design is brought forward. The theoretical result shows the reflectance spectrum of multi-wavelength DBR design is better than that of the conventional DBR design, which is important to enhance light extraction from LED..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 752 (2006)
Theoretical and Experimental Studies on Multi-Beam Interference by Using Pyramid Lens
[in Chinese], and [in Chinese]
A method of producing 2D and 3D optical lattices with multi-beam interference by using the pyramid lens and the top-chopped pyramid lens is proposed. The structures of 2D and 3D optical lattices formed by interference of multiple z-axis symmetrically distributed plane waves are numerically simulated and analyzed. The rA method of producing 2D and 3D optical lattices with multi-beam interference by using the pyramid lens and the top-chopped pyramid lens is proposed. The structures of 2D and 3D optical lattices formed by interference of multiple z-axis symmetrically distributed plane waves are numerically simulated and analyzed. The relation between the optical-field distribution and the light beam number is conducted, the interference field tends complicate with the rise of beam numbers, when the arrises of the pyramid are enough and the pyramid can be regarding as an axicon, the interference field becomes a Bassel distribution with a concentric circles structure. In the experiment, the multi-arris pyramid lens and the multi-arris top-chopped pyramid lens are used to generate optical lattices. The experimental results are quite consistent with the simulation results..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 757 (2006)
Physical Optics
Free-Propagation Corection of Few-Cycle Pulsed Beam with Constant Beam Waist
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
By use of the angular-spectrum analysis and the Fourier transform method, a correction method is obtained to describe the propagation of few-cycle pulsed beam with constant beam waist. The correspondingly simple approach, which is developed by a Taylor expansion of the known quasi-monochromatic light-beam solution, canBy use of the angular-spectrum analysis and the Fourier transform method, a correction method is obtained to describe the propagation of few-cycle pulsed beam with constant beam waist. The correspondingly simple approach, which is developed by a Taylor expansion of the known quasi-monochromatic light-beam solution, can be used to describe the propagation of few-cycle laser pulses with arbitrary temporal envelope and transversal profiles. The approximation solution of Gaussian pulsed beam with constant beam waist is obtained, propagation characteristics of the Gaussian pulsed beam are investigated in detail, and effects of some different spectra on pulse propagation are analyzed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 763 (2006)
Controlling the Duty Cycle of Photoresist Gratings by Setting the Guided-Wave Coupling Angles in Monitoring of Photoresist Development
[in Chinese], [in Chinese], and [in Chinese]
A new technique for controlling the duty cycle (ratio of ridge width to period) of photoresist gratings made on top of a multilayer dielectric stack is studied. It is used in conjunction with the real-time monitoring technique during photoresist development, and based on the principle that the effective refractive indeA new technique for controlling the duty cycle (ratio of ridge width to period) of photoresist gratings made on top of a multilayer dielectric stack is studied. It is used in conjunction with the real-time monitoring technique during photoresist development, and based on the principle that the effective refractive index of the leaky mode that has a strong evanescent tail in the cladding varies with the duty cycle of the grating situated at the interface between the top dielectric layer and the cladding. By applying the relationship of the coupling angle and duty cycle, a desired duty cycle can be obtained by terminating development when the leaky mode is excited under a preset incident angle. The experimental results showed that the duty cycle of the resulting grating can be adjusted by changing the incident angle. The work preliminarily establishes the feasibility of the technique. Experimental setup and procedure are presented, and the error sources and their influences are discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 767 (2006)
Rapid Communications
10.5 W Continuous-Wave Output from Yb∶Y2O3 Ceramic Disk Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A contimuous-wave (CW) output has been obtained from a polycrystalline 8% mole ratio Yb∶Y2O3 ceramic disk laser with end-pumping and double-pass absorption cavity, which is end-pumped by a collimated high-power laser diode with the central wavelength located at 970 nm, at room temperature. The threshold pump power of tA contimuous-wave (CW) output has been obtained from a polycrystalline 8% mole ratio Yb∶Y2O3 ceramic disk laser with end-pumping and double-pass absorption cavity, which is end-pumped by a collimated high-power laser diode with the central wavelength located at 970 nm, at room temperature. The threshold pump power of the laser is 7 W, and under pump power of 35 W a CW output power of 10.5 W at 1078 nm is obtained, with optical-optical conversion efficiency of 30% and slope efficiency of 37.5%. There exists a rough linear rise for the output power with the pump power. The higher output power and efficiency can be expectable by adopting higher pump power, optimizing the cavity parameters and decreasing influence of thermal effect..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 797 (2006)
Laser Diode-Pumped Efficient Tunable YbLYSO Laser
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
We demonstrate continuous-wave laser action in a Yb3+-doped lutetium Yttrium oxyorthosilicate (YbxLuyY1-x-y)2SiO5(YbLYSO) crystal (0.001≤x≤0.5, 0≤y≤0.8). In the free-running operation, we obtained an output power as high as 7.8 W centered about 1086 nm for a 2.5% output coupler, corresponding to a slope efficiency of 6We demonstrate continuous-wave laser action in a Yb3+-doped lutetium Yttrium oxyorthosilicate (YbxLuyY1-x-y)2SiO5(YbLYSO) crystal (0.001≤x≤0.5, 0≤y≤0.8). In the free-running operation, we obtained an output power as high as 7.8 W centered about 1086 nm for a 2.5% output coupler, corresponding to a slope efficiency of 64%. Using a SF14 prism as an intracavity tuning element, the tunability of the YbLYSO laser in the spectral range of 1014～1091 nm has been achieved..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 799 (2006)
Thin Films
Preparation of γ-LiAlO2 Layer on (11-20)Sapphire by Vapor Transport EquilibrationLiu Shiliang
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In order to find a new substrate which can probably substitute the sapphire for GaN epitaxy, a single phase and polycrystalline γ-LiAlO2 layer has been prepared by vapor transport equilibration (VTE) for 48 hours at 1000 ℃, 1030 ℃, 1050 ℃, 1070 ℃ and 1100 ℃, respectively. X-ray diffraction (XRD) and scanning electronicIn order to find a new substrate which can probably substitute the sapphire for GaN epitaxy, a single phase and polycrystalline γ-LiAlO2 layer has been prepared by vapor transport equilibration (VTE) for 48 hours at 1000 ℃, 1030 ℃, 1050 ℃, 1070 ℃ and 1100 ℃, respectively. X-ray diffraction (XRD) and scanning electronic microscope (SEM) have been used to characterize the phase, orientation and surface morphology. The results show that the preferred orientation of γ-LiAlO2 layer depends on temperature. The γ-LiAlO2 layer prepared at 1050 ℃ has a highly preferred [100] orientation. A biaxial tensile stress existing in (001) γ-LiAlO2 may contribute to the form of the preferred [100] orientation. The directional coherence of stripes on the surface of γ-LiAlO2 grains closely corresponds to the preferred orientation of γ-LiAlO2 layer. The above results indicate that the γ-LiAlO2/α-Al2O3 prepared by vapor transport equilibration under appropriate conditions probably provides a promising compound substrate which adapts to grow (1-100) GaN film..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 773 (2006)
Deposition of Carbon Nanotubes Film by LPCVD and Related Field Emission Property
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Carbon nanotubes (CNTs) were directly grown on nickel substrates by low pressure chemical vapor deposition (LPCVD) using acetylene-hydrogen as precursor. The reaction temperature was in the range of 500～800 ℃. Temperature effects on the growth and morphology of CNTs and their field emission properties were investigatedCarbon nanotubes (CNTs) were directly grown on nickel substrates by low pressure chemical vapor deposition (LPCVD) using acetylene-hydrogen as precursor. The reaction temperature was in the range of 500～800 ℃. Temperature effects on the growth and morphology of CNTs and their field emission properties were investigated. The growth rate of CNTs increased first with temperature increase from 500 ℃, and reached a maximal value at 650 ℃, then decreased when the temperature increased further. The morphologies and structures of deposited CNTs were characterized by scanning electron microscope and Raman spectroscopy. The diameter, length, uniformity and crystallinity of the deposited CNT also showed a temperature dependence. The field emission properties of the CNTs were tested, the field emission principle was studied deeply, and the results proved the temperature dependence of CNTs properties and the existance of optimization of temperature. The experimental result indicated that the morphology, structure and field emission properties of CNTs could be controlled by the reaction temperature in a certain range..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 777 (2006)
Optical Absorption Properties of Au-SiO2 Nanocomposites
[in Chinese], and [in Chinese]
Ion beam co-sputtering technique is used to deposit Au-SiO2 nanocomposite films on quartz at room temperature. The nanocomposite films are annealed at different temperatures from 500～900 ℃ for 5 minutes. The film phases are identified by X-ray diffraction (XRD),the XRD spectra of Au-SiO2 nanocomposite as-deposited and Ion beam co-sputtering technique is used to deposit Au-SiO2 nanocomposite films on quartz at room temperature. The nanocomposite films are annealed at different temperatures from 500～900 ℃ for 5 minutes. The film phases are identified by X-ray diffraction (XRD),the XRD spectra of Au-SiO2 nanocomposite as-deposited and annealed are obtained. Transmission electronic microscopy (TEM) is used to check Au particles distribution and size in the film annealed at 700 ℃. Optical absorption spectra are recorded in 190～1000 nm with a spectrometer. The absorption peak has a clear red-shift with increasing temperature in 500～700 ℃, and both position and intensity of the peak seem not to alter at higher temperature. It agrees well with the detection in XRD. With Drude model the absorption peak is explained theoretically..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 783 (2006)
Wide-Angle X-Ray Supermirror Design Using Simulated Annealing Algorithm
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The design of wide angle X-ray supermirror, wide band-pass multilayer optical elements operating in the hard X-ray region is attributed to the global optimization of the multi-dimensional extremum of continuous variables. Lack of powerful optimization method is the key obstacle to this problem. Simulated annealing algoThe design of wide angle X-ray supermirror, wide band-pass multilayer optical elements operating in the hard X-ray region is attributed to the global optimization of the multi-dimensional extremum of continuous variables. Lack of powerful optimization method is the key obstacle to this problem. Simulated annealing algorithm is a simple and universal global optimization method. Based on the theory of optical multilayers, a new method of designing wide angle X-ray supermirror using simulated annealing algorithm is presented. The coating materials pair W/C is selected by the combination of the Spiller' and Yamamoto' criterions. The designed supermirror with high and flat reflectivity of 20%, over a grazing incident angle range 0.9°～1.1° at the wavelength of Cu Kα line is completed. Furthermore, the improved adaptive simulated annealing algorithm is used to obtain a better design result. The validity of the proposed algorithm is shown by the example involving multilayer design..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 787 (2006)
Color Filter Design Based on Rugate Wavelets Theory
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The gradient refractive index coating overcomes the initial disadvantages of the traditional discrete coating by eliminating the interfaces. A way of designing this kind of coatings is provided. Based on the wavelets theory and the gradient refractive index antireflection theory, with the high-reflection discrete multiThe gradient refractive index coating overcomes the initial disadvantages of the traditional discrete coating by eliminating the interfaces. A way of designing this kind of coatings is provided. Based on the wavelets theory and the gradient refractive index antireflection theory, with the high-reflection discrete multilayer dielectric coatings as the reference, the design principle with Rugate filters of different type and color filters is presented, and red, blue and green color filters with high spectral performance are designed theoretically according to the targets of color filters used in the rear display system. The angular sensitivity and polarization effect of the new design are compared with the multilayer coating obtained by the traditional high-reflection coating stacking method, and it is found that the former is less sensitive to the incidence angle and exhibits less polarization effect..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 26, Issue 5, 792 (2006)
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