Photodiodes seek desirable photons

Optical communications, biomedical-instrumentation, spectroscopy, thermal-imaging, and other analysis systems require specialized sensors to capture wavelengths. Addressing that need, the G8370-10 indium-gallium-arsenide PIN photodiode from Hamamatsu monitors laser diodes over the 0.9- to 1.7-micron range. Peak sensitivity is 0.95A/W at 1.55 microns, and typical dark current is 0.2 mA. The 16.5×15×12.7-mm, ceramic-packaged device has a 10-mm-diameter active area and operates from –15 to +70°C. Typical uniformity of the photo response is within –2% for this $3400 photodiode.

Another photodiode, the SU1024LE from Sensors Unlimited, meets the needs of linear-photodiode-array applications (Picture). This 1024-element array with 25-micron channel spacing and 500-micron-high pixels has closely matched element uniformity and includes a CMOS-readout IC for improved noise immunity and sensitivity. You provide a 5V power supply and two digital control lines for operation. Operating wavelength range is 0.8 to 1.7 microns, and you can read pixels at speeds as high as 10⁷ pixels/sec; the full-well capacity is 1.3×10⁸ electrons. At peak-response wavelength of 1.5 microns, responsivity is at least 10.5 nV/photon, and minimum quantum efficiency is 70%. The $8000 sensor is pin-compatible with previous 256- and 512-element arrays from the vendor, and comes with a "no-dead-pixel" guarantee.

Hamamatsu Corp, 1-800-524-0504, http://usa.hamamatsu.com.

Sensors Unlimited Inc, 1-609-520-0610, www.sensorsinc.com.