Large-area low-noise resonant photodetector for high-sensitivity stimulated Raman scattering spectroscopy and imaging

Area of Science:

• Optics and Photonics
• Biomedical Imaging
• Quantum Optics

Background:

• Stimulated Raman Scattering (SRS) detection requires sensitive amplifiers for large-area photodiodes.
• High junction capacitance in large photodiodes presents challenges for amplifier stability and noise performance.
• Conventional detectors often saturate under high optical power, limiting characterization of quantum states.

Purpose of the Study:

• To present a novel low-noise compensated tuned amplifier (cTAMP) architecture.
• To optimize the amplifier for large-area photodiodes in SRS detection.
• To demonstrate its capability for high-sensitivity quantum optics and biomedical imaging applications.

Main Methods:

• Integrated a tunable RLC feedback network with a matching compensation inductor.
• Designed the amplifier to overcome high junction capacitance of large photodiodes (10x10 mm^2).
• Configured a detector with a 20 MHz center frequency and 1 MHz bandwidth.

Main Results:

• Achieved an output-referred noise floor of 31 nV/√Hz.
• Enabled shot-noise-limited linear operation from 0.1 mW to 36 mW optical power.
• Demonstrated wide dynamic range and low noise for characterizing high-power squeezed states and enabling ultrafast SRS microscopy.

Conclusions:

• The cTAMP-based detector offers a versatile platform for high-sensitivity quantum optics and biomedical imaging.
• The design facilitates biocompatible SRS microscopy with milliwatt-level excitation for live cell imaging.
• Potential for extension to other modulation-based optical measurements exists.