Four-point bisensitivity velocity interferometer with a multireflection etalon

Area of Science:

• Optical physics
• Metrology
• Materials science

Background:

• Accurate measurement of dynamic velocities is crucial in various scientific and engineering fields.
• Existing velocity interferometry systems can be limited by etalon size, cost, and sensitivity for small velocity detection.

Purpose of the Study:

• To propose and demonstrate a novel four-point bisensitivity velocity interferometer system for any reflector (VISAR).
• To enhance the measurement accuracy of small velocities using a cost-effective and compact delay etalon.
• To achieve improved velocity per fringe resolution.

Main Methods:

• Development of a renovative delay etalon with a new film-coating strategy.
• Utilizing two laser beams with different incident angles through the etalon.
• Optimizing the etalon for multiple laser beam penetration.
• Implementing a four-point bisensitivity configuration.

Main Results:

• The new VISAR system enables accurate measurement of small velocities with a relatively short and inexpensive etalon.
• The delay time is effectively increased by utilizing different reflection paths within the etalon.
• A velocity per fringe reduction of approximately three times was achieved for the laser beam with a smaller incident angle.
• The system demonstrated velocity per fringe capabilities of 100 and 350 m/s with a 200 mm diameter, 150 mm length etalon.
• Successful measurement of a steel flyer driven by an explosive was conducted.

Conclusions:

• The proposed four-point bisensitivity VISAR with a renovative delay etalon offers a significant advancement in dynamic velocity measurement.
• This technology provides a more sensitive, compact, and cost-effective solution for high-precision velocity measurements.
• The system is applicable to various scenarios requiring accurate dynamic velocity tracking, such as explosive-driven material experiments.