• Infrared and Laser Engineering
  • Vol. 54, Issue 5, 20240615 (2025)
Xiaoshuai MA1, Dongxu ZHU1, Zhuoren WAN1, and Ming YAN1,2
Author Affiliations
  • 1State Key Laboratory of Precision Spectroscopy, and Hainan Institute, East China Normal University, Shanghai 200062, China
  • 2Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing 401120, China
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    DOI: 10.3788/IRLA20240615 Cite this Article
    Xiaoshuai MA, Dongxu ZHU, Zhuoren WAN, Ming YAN. Two-dimensional infrared light field manipulation based on a digital micromirror device(invited)[J]. Infrared and Laser Engineering, 2025, 54(5): 20240615 Copy Citation Text show less

    Abstract

    ObjectivePicosecond pulsed lasers with a GHz repetition rate are commonly used in biophotonics, laser industrial processing, and high-speed precision measurement due to their high repetition rate and short pulse duration. To control these systems, it is necessary to modulate the light field of the pulses. A 4F system is typically employed to spatially separate the frequency components of the laser. Conventional systems rely on diffraction gratings, which are limited by groove density and size, restricting spectral resolution to the nanometer scale. Higher spectral resolution can be achieved with echelon gratings that use higher diffraction orders, but these systems are often complex, sensitive to noise, and expensive. To address these challenges, this paper proposes combining a Virtually Imaged Phased Array (VIPA) with a diffraction grating to achieve two-dimensional spatial dispersion. This method enhances the generation and modulation of picosecond pulses with GHz repetition rates while improving anti-interference capabilities and overall spectral resolution.MethodsThis paper presents a two-dimensional light field modulation device based on a Digital Micromirror Device (DMD) (Fig.1). The system utilizes a VIPA to disperse the frequency of the input pulsed laser in the longitudinal direction. Additionally, a diffraction grating is employed to separate the frequency components in the lateral direction. The DMD is positioned as a mask in the Fourier plane of the system to achieve spatial modulation of the light frequency. The modulated light is then directed to a spectrometer or autocorrelator to evaluate the modulation effect.Results and DiscussionsThe infrared camera was utilized to examine the spatial dispersion of optical frequencies in the Fourier plane. In this plane, the optical frequencies are distinctly separated, forming a clear linear array (Fig.2). A target was positioned in the Fourier plane for imaging, allowing us to investigate the relationship between two-dimensional space and optical frequency. The results of the spectral imaging correspond closely with the digits on the target (Fig.3). A DMD was placed at the focal plane to manipulate the two-dimensional optical field, achieving a signal-to-noise ratio of 46.02 dB (Fig.4). The system produced more than 52 pulses, with a repetition frequency of 16.67 ps (Fig.5), and allowed for relative delay control of high-repetition pulses at intervals of 250 ps and 500 ps (Fig.6).Conclusions To address the need for generating and controlling high-repetition-rate picosecond pulse light, a two-dimensional optical field control system based on a DMD is proposed. This system employs a virtual phase array and a diffraction grating to disperse the frequency of the input pulsed laser in two-dimensional space. A DMD is positioned at the Fourier plane of the system to facilitate optical field control. The physical model of two-dimensional optical frequency dispersion is analyzed to inform the selection of the key components of the system. The system's capability for two-dimensional optical frequency dispersion is validated through experimental results, which demonstrate that the optical field in the Fourier plane forms a linear array, with its spatial position corresponding to the optical frequency. To confirm the feasibility of the proposed system, a DMD is utilized to control the spatially dispersed optical frequencies, successfully generating more than 52 pulses with a repetition frequency of 16.67 ps. Additionally, relative delay control of 250 ps and 500 ps is achieved. The system showcases a signal-to-noise ratio of 46.02 dB. The proposed two-dimensional optical field control system demonstrates high spectral resolution and stability, features a high modulation speed, and provides an effective and practical approach for precisely controlling high-repetition-rate picosecond pulses.
    Xiaoshuai MA, Dongxu ZHU, Zhuoren WAN, Ming YAN. Two-dimensional infrared light field manipulation based on a digital micromirror device(invited)[J]. Infrared and Laser Engineering, 2025, 54(5): 20240615
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