A laser monitor with a single laser has been used in an approach that would be similar to LIDAR to monitor the thoracic wall displacement (Kondo et al 1997).
In June 2019, the MIT Tech review reported that the Pentagon (the Combatting Terrorism Technical Support Office or CTTSO of the U.S. Special Forces) has a laser for identification of cardiac signatures from a distance of 200 m and over typical clothing. The device called “Jetson” developed by Ideal Innovations Inc. uses an infrared laser to detect the movement of the body surface caused by the heartbeat using laser vibrometry. It is noted that the device was adapted from an off-the-shelf device for remote measurement of vibration for structures such as wind turbines. Adaptation included a special gimbal to stabilize the invisible laser spot (having the size of a quarter) on the remote target. A time interval of 30 seconds is currently required for signal return, therefore the subject should be either sitting or standing.
Figure 1: MIT Tech Review post refering to Jetson