A 1024× 8, 700-ps time-gated spad line sensor for planetary surface exploration with laser raman spectroscopy and libs

Abstract

A 1024× 8 time-gated, single-photon avalanche diode line sensor is presented for time-resolved laser Raman spectroscopy and laser-induced breakdown spectroscopy. Two different chip geometries were implemented and characterized. A type-I sensor has a maximum photon detection efficiency of 0.3% and median dark count rate of 80 Hz at 3 V of excess bias. A type-II sensor offers a maximum photon detection efficiency of 19.3% and a median dark count rate of 5.7 kHz at 3 V of excess bias. Both chips have 250-ps temporal resolution and fast gating capability, with a minimum gate width of 1.8 ns for type I and 0.7̃ns for type II. Raman spectra were successfully observed from natural minerals, such as calcite and willemite. With the use of subnanosecond gating, background fluorescence was significantly reduced. © 2013 IEEE.