Fig. 1. (a) Optical microscopy image of the CVD grown PtSe2 film. (b) Raman spectrum of PtSe2 film. (c) AFM image of the transferred PtSe2 and the typical height profile along the white dashed line. XPS spectra of (d) the PtSe2 film, (e) the Pt 4f region, and (f) the Se 3d region.

Fig. 2. (a) Microscope image of the all-optical modulator where PtSe2 film fully covers the whole device. (b) A zoom-in on the part of the MRR shows uniformly transferred thin film. (c) Cross section of the PtSe2-on-silicon structure. (d) Transmission spectra of the MRR without (brown) and with (blue) the PtSe2 film (normalized respectively). (e) All-optical modulation mechanism and experimental setup of the PtSe2-based modulator. TLS, tunable laser source; ASE, amplified spontaneous emission; PC, polarization controller; SMF, single-mode fiber; OSA, optical spectrum analyzer; PD, photodetector; OSCP, oscilloscope.

Fig. 3. (a) Static spectral response for different pump powers. (b) Measured resonance shift versus pump power and the corresponding linear fitting curves, for pristine PtSe2 device (red) and the device after 3-month air exposure (blue).

Fig. 4. (a) Pump light with 100 Hz frequency and (b) the corresponding modulated signal light. (c) Several signal waveforms at different frequencies. (d) V_pp versus modulation frequency.

Fig. 5. Infrared thermograms of the PtSe2 modulator with pump powers of (a) 50 mW and (b) 500 mW. (c) Surface temperature change of the modulator versus pump power.

Fig. 6. (a) Optical microscopy image of the pure silicon MZI. (b) Static spectral response for different pump powers. (c) Measured resonance shift versus pump power and the corresponding fitting curve.

Table 1. Comparison of Reported All-Optical Modulators Based on the Photothermal Effect of 2D Materials