[19p-Z22-1~16] 3.13 Semiconductor optical devices

▲ [19p-Z22-14] Stimulated Raman Scattering CMOS Image Sensor with In-Pixel Double Modulation Technique

〇(D)KorakkottilKunhiMohd Bin Shukri¹, De Xing Lioe², Juyeong Kim¹, Keita Yasutomi², Keiichiro Kagawa², Shoji Kawahito² (1.Graduate School of Science and Technology, Shizuoka University., 2.Research Institute of Electronics, Shizuoka University.)

Keywords:Stimulated Raman Scattering, CMOS image sensor, lock-in amplifier

Stimulated Raman Scattering (SRS) is an optical microscopy known as a label-free, noninvasive imaging technique to observe the dynamic process of biological events and vibrational properties of gases, liquids, and solids. In typical SRS microscopy, SRS signal is produced when the optical angular frequency difference between the pump and the Stokes laser resonates with the sample vibrational frequency. However, the SRS signal produced is small, where it is in the range of 10^-5 to 10^-4 on top of a very large offset, and difficult to digitize. In this work, a technique utilizing CMOS lock-in pixel for SRS signal detection is developed. Gated photo-detector so-called lateral electric field modulator (LEFM), is used to detect and demodulate a pulse train of photo-currents that contains SRS signal. Switched-capacitor readout circuit is designed to extract the SRS signal from the large offset. Double modulation technique is implemented for noise reduction. In the implementation, fully-differential folded cascode amplifier operating at 20 MHz and 5 MHz is designed for the system operation. As for the result, the simulation shows that the SRS signal can be acquired successfully. The system is able to operate correctly by giving the null output when the SRS signal is not present.