Geiger-mode laser vibrometry methods and systems

A device for laser vibrometry, comprising:

• a splitter to split an input laser beam into a first laser beam and a second laser beam;
• a first optical component positioned to direct the first laser beam toward a target;
• a second optical element positioned to receive a laser beam that is either reflected from, or transmitted through, the target, the reflected or the transmitted laser beam comprising single photon arrivals that include information corresponding to vibrations of the target, each single photon arrival separated in time from another single photon arrival;
• an avalanche photodiode (APD) array configured to operate in a Geiger mode and positioned to receive and to detect the single photon arrivals;
• and
• a processor, coupled to the APD array, that is configured to:
• receive detection information as part of a first time-series corresponding to the single photon arrivals;
• determine, based on two or more of the single photon arrivals, a discrete time sequence having a binary value, wherein a first binary value is indicative of an arrival and a second binary value is indicative of a lack of an arrival of a photon at a corresponding discrete time point;
• and
• generate a second time-series by assigning a nonbinary value to each of the discrete time points, wherein each of the assigned non-binary values corresponding to the second binary values represents a separation between two of the two or more of the single photon arrivals that is determined based on a number of discrete time points lacking a photon arrival prior to receiving a photon, and wherein processing the second time-series enables extraction of the information corresponding to vibrations of the target.

A non-transitory computer-readable storage medium having instructions stored thereupon for laser vibrometry, comprising:

• instructions for receiving, using a photodiode configured to operate in a Geiger mode, a first time-series of single photon arrivals corresponding to a laser beam reflected from or transmitted through a target, the single photon arrivals including information corresponding to vibrations of the target, each single photon arrival separated in time from another single photon arrival;
• instructions for determining, based on two or more of the single photon arrivals, a discrete time sequence having a binary value, wherein a first binary value is indicative of an arrival and a second binary value is indicative of a lack of an arrival of a photon at a corresponding discrete time point;
• and
• instructions for generating a second time-series by assigning a non-binary value to each of the discrete time points, wherein each of the assigned non-binary values corresponding to the second binary values represents a separation between two of the two or more of the single photon arrivals that is determined based on a number of discrete time points lacking a photon arrival prior to receiving a photon,
• wherein processing the second time-series enables extraction of the information corresponding to vibrations of the target.