Laser interferometer

Laser interferometer comprising a laser light source providing at least one light beam at two distinct frequencies, a beam splitter for splitting the at least one light beam into reference and measurement beams, a first reflector and a second reflector for reflection of the reference and measurement beams, and at least one detector for detection...

Frequency stabilized three mode HeNe laser using nonlinear optical phenomena

Accurate and traceable length metrology is employed by laser frequency stabilization. This paper describes a laser frequency stabilzation technique as a secondary standard with a fractional frequency stability of 5.2×10?10 with 2 mW of power, suitable for practical applications. The feedback stabilization is driven by an intrinsic mixed mode...

High resolution heterodyne interferometer without detectable periodic nonlinearity

A high resolution heterodyne laser interferometer without periodic nonlinearity for linear displacement measurements is described. It uses two spatially separated beams with an offset frequency and an interferometer configuration which has no mixed states to prevent polarization mixing. In this research, a simple interferometer configuration for...

Design of a folded, multi-pass Fabry–Perot cavity for displacement metrology

We present a folded, multi-pass cavity design for displacement measuring Fabry–Perot interferometry. The cavity length is designed to be one-quarter of the physical length needed for a typical Fabry–Perot interferometer by using a quarter-wave plate and a retroreflector. This enhances the displacement sensitivity by a factor of four, allowing...

Balanced interferometric system for stability measurements

We describe two different, double-sided interferometer designs for measuring material stability. Both designs are balanced interferometers where the only optical path difference is the sample and the reference beams are located within the interferometer. One interferometer is a double-pass design, whereas the other is a single-pass system. Based...

Simple heterodyne laser interferometer with subnanometer periodic errors

We describe a simple heterodyne laser interferometer that has subnanometer periodic errors and is applicable to industrial fields. Two spatially separated beams can reduce the periodic errors, and the use of a right-angle prism makes the optical configuration much simpler than previous interferometers. Moreover, the optical resolution can be...