Simultaneous determination of optical loss, residual reflectance and transmittance of highly anti-reflective coatings with cavity ring down technique

Abstract

Cavity ring down (CRD) technique was employed to measure optical losses (absorption and scattering losses), residual reflectance and transmittance of anti-reflectively (AR) coated laser components with transmittance higher than 99.9%. By inserting the AR coated laser component with parallel optical surfaces into the ring-down cavity and measuring the ring-down time versus the angle of incidence with respect to the surface normal, the optical loss and residual reflectance of the laser component were determined respectively at normal and out-of-normal incidences with repeatability of part-per-million level. The transmittance was also determined simultaneously. Experimental results demonstrated that CRD is a simple, inexpensive and fast technique for highly accurate measurements of optical loss, residual reflectance, and transmittance of AR coated laser components widely used in high-power laser systems.

Extinction measurement with open-path cavity ring-down technique of variable cavity length

“…An optical feedback CRD (OF-CRD) [22][23][24] scheme is used in the variable-cavity-length OPCRD measurements performed in a normal laboratory clean room with a dust pelletizing system (DPS) to control the particle concentration. A schematic diagram of the experimental setup for measuring optical extinction is shown in Fig.…”

Low-cost NO2 trace concentration measuring device using a broadband diode laser and a customized cavity

“…To reduce errors caused by the structure of the gases chamber, a customized linear cavity with four mixing rooms was designed and machined. Compared with the V-shaped structure, [11][12][13] the linear-shaped cavity has a lower mirror transmitted and absorbed loss and a higher detection sensitivity. [14][15][16][17] In this work, we develop a low-cost and high-detection accuracy NO 2 trace concentration measuring device based on CRDS, which uses a broadband LD and caon get a strong and stable ring-down signal even without a PMT.…”

“…To reduce errors caused by the structure of the gases chamber, a customized linear cavity with four mixing rooms was designed and machined. Compared with the V-shaped structure, 11 – 13 the linear-shaped cavity has a lower mirror transmitted and absorbed loss and a higher detection sensitivity 14 – 17 …”

Simultaneous measurements of s- and p-polarization reflectivity with a cavity ring-down technique employing no polarization optics

“…The polarization states of light should be considered as a source of uncertainty when accurate measurements are needed and the degree of polarization of incident light is unknown. In this Letter, the CRD technique [19][20][21][22] is adopted for accurate and simultaneous measurements of R s and R p of HR mirrors without employing any polarization optical components. By employing a randomly polarized laser beam as the light source and fitting the recorded ring-down signal to a double-exponential function to extract simultaneously the ring-down time of s-and p-polarized light, the s-and p-polarization reflectances R s and R p of HR mirrors are determined simultaneously with high precision.…”