Pseudo-random single photon counting for time-resolved optical measurement

Abstract

We report a new time-resolved optical measurement method which combines single photon counting and the spread spectrum time-resolved optical measurement method. A laser diode modulated with pseudo-random bit sequences replaces the short pulse laser used in conventional time-resolved optical systems, while a single photon detector records the pulse sequence in response to the modulated excitation. Periodic cross-correlation is used to retrieve the impulse response. Feasibility of our approach is validated experimentally. A rise time around 150 picoseconds has been achieved with our prototype. Besides high temporal resolution, the new method also affords other benefits such as high photon counting rate, fast data acquisition, portability, and low cost.

Ultra Storage-Efficient Time Digitizer for Pseudorandom Single Photon Counter Implemented on a Field-Programmable Gate Array

“…A comparison between our PRSPC and the conventional TCSPC approach had been discussed in [8] and the simulation results had shown that the PRSPC system can rebuild the original waveform with high accuracy theoretically.…”

“…While its accuracy may be marginally inferior to that of the conventional TCSPC technique, PRSPC has two main advantages over TCSPC (see [8] for a comparison).…”

“…As a solution to this problem, a pseudorandom bit-sequence-based single photon counting (PRSPC) method has been proposed by our group [8]. In PRSPC, a low-power laser diode modulated by a pseudorandom bit sequence replaces the pulsed laser as the light source.…”

“…Another advantage of this system is that it can differentiate photons detected at different time delays from the environmental noise and interference. The detail of PRSPC was introduced by Zhang et al in a separate paper [8].…”

A spread spectrum approach to diffusive optical spectroscopy and imaging

“…Time-Domain (TD) systems are commonly used to perform NIR spectroscopy, but this technique has some limitations, as the high cost of equipment, the acquisition length and the sensitivity to ambient light. A novel, spread spectrum approach was presented in [1] where continuous wave (CW) laser sources are modulated by a pseudo-random bit sequence (PRBS). This approach can overcome the latter limitations, adding the advantages of CW systems (low cost of components, lower sensitivity to ambient light and shorter acquisition time).…”