Related Experiment Video
Updated: Jun 27, 2026

Quantum State Engineering of Light with Continuous-wave Optical Parametric Oscillators
Published on: May 30, 2014
Closed-loop phase-shifting homodyne interferometry using heterodyne phase detection
1National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 3, Tsukuba, Ibaraki, Japan. y-bitou@aist.go.jp
Abstract:
A phase-shifting homodyne interferometer with feedback control by heterodyne phase detection is developed. The backreflected beam from a reference flat with a small wedge angle and an internal heterodyne detection system are utilized to obtain heterodyne beat signals for the feedback error signal. Using a digital high-speed lock-in amplifier, interference fringe stabilization, and accurate pi/2 phase shifts when micrometer-order vibrations are applied have been successfully demonstrated with a general nonpolarizing homodyne interferometer configuration.
Related Concept Videos
Phase Contrast and Differential Interference Contrast Microscopy
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
Interference: Path Lengths
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...
Time and frequency -Domain Interpretation of Phase-lead Control
The design of phase-lead control involves the strategic placement of poles and zeros to balance steady-state error and system...
Time and frequency -Domain Interpretation of Phase-lag Control
Phase-lag controllers do not place a pole at zero, but instead influence the steady-state error by amplifying any finite,...
Doppler Effect - II

