Light Detection And Ranging (LIDAR) is a technology that involves transmitting laser light at a target and then detecting the light that is reflected or scattered by this target for measurement and analysis. In its simplest form, LIDAR is used in laser ranging, in which distances are determined by measuring the time it takes for light pulses to travel to and from a solid target. More complex applications, such as atmospheric or meteorology studies, also measure the intensity of scattered light at specific wavelengths in order to evaluate the concentration of particular compounds at various altitudes. Multiple wavelengths can be used to achieve a better correlation of scatter measurements.

Choosing a detector for LIDAR requires consideration of the detection wavelength(s), the transit time spread (TTS) or jitter, and the amount of light expected. TTS is related to the required distance resolution, while the amount of reflected light is proportional to two things: the distance between the target and detector, and the concentration of the targeted compound. Because the detectable light level is often very low, the most suitable detector for this application is one that has internal gain, such as an avalanche photodiode (APD) or a photomultiplier tube (PMT). In the case of PMTs, a technique called gating is used to protect the tube from unexpectedly large reflections.

• H10304 series PMT high-speed gated PMT module: compact unit with built-in metal package PMT and gate circuit. 100 ns minimum gate width, 100 kHz repetition rate. Various spectral response ranges are available.
• H9170-75 near-infrared PMT module: capable of photon counting up to 1.7 um, and can be used for 1.55 um (eye safe) operation. Also features solar-blind response.
• H7680 high-speed gated PMT module: for UV-visible spectrum.
• R5916U series MCP-PMT: microchannel plate PMTs with high-speed gating function by low supply voltage. 5 ns gate width.
• C5658 silicon APD module: up to 1 GHz, suitable for NIR measurements.
• C5331 silicon APD module: up to 100 MHz, suitable for visible or NIR measurements.
• Silicon avalanche photodiodes: fast time response, low dark current, and high sensitivity. Available in various active area sizes and package types.

Please contact us for information on other products which can be used for this application.