MIT LL No. MS-43282, ESC No. 09-1097

1. Zero Read Noise Detectors for the TMTDon Figer, Brian Ashe , John Frye, Brandon Hanold, Tom Montagliano, Don Stauffer (RIDL), Brian Aull, Bob Reich, Dan Schuette, Jim Gregory, Erik Duerr, Joseph Donnelly (MIT/LL) MIT LL No. MS-43282, ESC No. 09-1097

2. Outline Motivation Why pursue photon-counting technology? Why use Geiger-mode avalanche photodiodes (APDs)? Moore Detector for TMT Heritage: LIDAR Conclusions

3. Outline Motivation Why pursue photon-counting technology? Why use Geiger-mode avalanche photodiodes (APDs)? Moore Detector for TMT Heritage: LIDAR Conclusions

4. Why pursue photon-counting technology? Photon-counting detectors effectively have zero read noise. In low light applications, read noise can dominate signal-to-noise ratio. Many applications can become low light applications with higher resolutions. spectroscopy time-resolved photometry fast wavefront sensing and guiding

5. Detectivity (higher is better)

6. Exposure Time to SNR=1

7. Example for Planet Imaging The exposure time required to achieve SNR=1 is dramatically reduced for a zero noise detector compared to detectors with state of the art read noise.

8. Why use Geiger-Mode Avalanche Photodiodes (GM-APDs)? produce easily distinguishable high voltage pulse per photon have zero “excess noise factor” allow for hybridization and bonding to non-optical detecting materials allow photon counting inside each pixel for high frame rates and time tagging have demonstrated excellent performance for LIDAR applications

9. Gain of an APD M Ordinary photodiode Linear-mode APD Geiger-mode APD 100 10 1 0 Breakdown Response to a photon ∞ I(t) M 1

10. Geiger-Mode Imager: Photon-to-Digital Conversion APD/CMOS array Lenslet array Focal-plane Digitallyencodedphotonflight time Pixel circuit Digital timing circuit photon APD Quantum-limited sensitivity Noiseless readout Photon counting or timing

11. Outline Motivation Why pursue photon-counting technology? Why use Geiger-mode avalanche photodiodes (APDs)? Moore Detector for TMT Heritage: LIDAR Conclusions

12. Moore Detector Project Goals Operational Photon-counting Wide dynamic range: flux limit to 108 photons/pixel/s Streaming readout adaptive optics imaging multiple target tracking Time delay and integrate Technical Backside illumination for high fill factor Demonstrate 25 mm pitch imager with streaming, single photon, readout

13. Moore Photon Counting Imager

14. Moore Photon Counting Imager

15. Moore Detector Project Status A 256x256x25mm readout integrated circuit is being fabricated. InGaAs test diodes are being fabricated. Silicon GM-APD arrays have been fabricated and will be bump-bonded to the new readout circuit. Photon-counting electronics are being built. Testing will begin later in 2009. Depending on results, megapixel silicon or InGaAs arrays will be developed.

16. Overview of Pixel Operation Pixel Architecture

17. ROIC Pixel Layout (2x2 pixels) metal bump bond pad core (active quench, discriminator, APD latch) 2 pixels, 50 mm counters (4 pixels) counter rollover latch 2 pixels, 50 mm

18. InGaAs Development 3 APD designs grown and fabricated 2-mm-wide avalanche region (all InP) 3-mm-wide avalanche region (all InP) 2-mm-wide avalanche region (InGaAs absorber) Room-temperature CV measurements made Devices in packaging for low temperature measurements

19. Outline Motivation Why pursue photon-counting technology? Why use Geiger-mode avalanche photodiodes (APDs)? Moore Detector for TMT Heritage: LIDAR Conclusions

20. Si APD/CMOS Development History 4x4 arrays wire bonded to 16-channel CMOS readout 32x32 arrays fully integrated with 32x32 CMOS readout 64 x 64 arrays 3D-integrated with 2 tiers of SOI CMOS APD’s Discrete 4x4 arrays 256 x 256 arrays 1996 2009 not to scale

21. Imaging system photon starved. Each detector must precisely time a weak optical pulse. Microchip laser Geiger-mode APD array LIDAR Imaging System Color-codedrange image

22. These arrays will be fabricated for back-illumination with bump bonding, enabling high performance in a space-qualifiable focal plane. The design of the ROIC will be finished by the end of 2009, with fabrication starting in early 2010. Funding: $546,000 Duration: 3 years (2008-2010) High field multiplier Low field Medium low field absorber A LIDAR Imaging Detector for NASA Planetary Missions

23. 32x32 APD/CMOS Array with Integrated GaP Microlenses

24. Laser Radar Brassboard System (Gen I) 4  4 APD array External rack-mounted timing circuits Doubled Nd:YAG passively Q-switched microchip laser (produces 30 µJ, 250 ps pulses at  = 532 nm) Transmit/receive field of view scanned to generate 128  128 images Taken at noontime on a sunny day

25. Conventional vs LIDAR Image Conventional image

26. 3D Imaging of Model Airplane Multiple-frame coincidence processing of ~3-4 frames removes isolated dark counts Image quality excellent due to low optical cross-talk between pixels Single Frame 3D Display of Processed Image, Probability of Detection Color-code Color-code: 1 m range display Airplane hanging on 6 mm rope

27. Rotatable 3D Images of Multiple Objects 128x128 images recorded with scanned 4x4 array at 1.06 mm Coincidence processed to remove background/dark counts Dark blue equivalent to <2 photon average return (right image) Color-coded by Distance Color-coded by Detection Probability

28. Outline Motivation Why pursue photon-counting technology? Why use Geiger-mode avalanche photodiodes (APDs)? Moore Detector for TMT Heritage: LIDAR Conclusions

29. Conclusions Large-format photon-counting imaging detectors are within reach. We are funded to make 256x256 and megapixel devices. A 256x256 detector silicon-based array should be in testing by the end of the year. The devices will be implemented in a broad range of low light level and LIDAR timing applications.