Angle scintillations in the laser return from a retroreflector

Flexible corner cube retroreflector array for temperature and strain sensing

Optical sensors for detecting temperature and strain play a crucial role in the analysis of environmental conditions and real-time remote sensing. However, the development of a single optical device that can sense temperature and strain simultaneously remains a challenge. Here, a flexible corner cube retroreflector (CCR) array based on passive dual optical sensing (temperature and strain) is demonstrated. A mechanical embossing process was utilised to replicate a three-dimensional (3D) CCR array in a soft flexible polymer film. The fabricated flexible CCR array samples were experimentally characterised through reflection measurements followed by computational modelling. As fabricated samples were illuminated with a monochromatic laser beam (635, 532, and 450 nm), a triangular shape reflection was obtained at the far-field. The fabricated flexible CCR array samples tuned retroreflected light based on external stimuli (temperature and strain as an applied force). For strain and temperature sensing, an applied force and temperature, in the form of weight suspension, and heat flow was applied to alter the replicated CCR surface structure, which in turn changed its optical response. Directional reflection from the heated flexible CCR array surface was also measured with tilt angle variation (max. up to 10°). Soft polymer CCRs may have potential in remote sensing applications, including measuring the temperature in space and in nuclear power stations.

A flexible corner cube retroreflector (CCR) array based passive dual sensing is demonstrated to measure external stimuli (temperature/mechanical force as weight suspension).

Phase-conjugated directional diffraction from a retroreflector array hologram

A corner cube retroreflector (CCR) consists of three perpendicular flat surfaces and reflects the incident light back to its source.

Statistical properties of He-Ne laser radiation reflected through a turbulent atmosphere

Statistical properties of a He-Ne laser beam (0.63 microm) propagating through atmospheric folded paths of 1 and 12 km were investigated experimentally using direct and heterodyne detection. Measured scintillation histograms, power spectra, time autocorrelations, and phase fluctuations are reported. The turbulence parameters derived from the optical measurements were found to be in good agreement with those obtained from measurements of in situ temperature fluctuations.

Atmospheric distortions in a retroreflected laser signal

This paper presents and analyzes a model for the instantaneous received field that has been transmitted from a laser and then retroreflected from a corner cube, all in the presence of atmospheric turbulence and attenuation. The characteristics of this field are examined as a function of distance from the axis of the transmitted laser beam, and the merits of using shared optics (coaxial transmitter/receiver) from geometric and atmospheric considerations are examined. in particular, it is shown that angle-of-arrival (AOA) fluctuations induced by turbulence would be self-corrected in a retrosystem for a shared-optics configuration only if the transceiver and retroreflector are in each other's effective near fields or are separated by less than a self-correction range as defined in the text. The results are shown to be in agreement with recent experimental observations.