G. Rajalakshmi & Pranav Shirhatti receive i-HUB Quantum Technology Foundation grant

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Lasers play a central role in several science and technology domains ranging from communication, bio-medical applications, molecular identification to atomic clocks. Many of these applications require the wavelengths of lasers to be known very well. Typically, devices based on interference of light, known as wavelength-meters or wavemeters in short, are used for such applications. Among different interferometer designs, Fizeau interferometer is one of the leading candidates for wavemeter applications as it is compatible with both continuous and pulsed lasers and having no moving components makes it very robust for on-field deployment.

A typical Fizeau interferometer-based wavemeter consists of several stages giving rise to a high accuracy and sensitivity to small changes in wavelength (precision). However, building such high precision multistage interferometer is challenging, requiring access to sophisticated manufacturing facilities ultimately leading to high costs. Our recently developed cross fringe Fizeau interferometer design [1] overcomes this limitation and can be built easily entirely using off the shelf optical components. In this design by means of spreading the interference pattern in two dimensions, multistage performance can be easily realized. At the same time the power of modern-day imaging sensors (cameras), thanks to the rapid developments in the smartphone cameras, can be leveraged. Overall, this design is easy to build, cost effective and an accuracy of 1 part per million and precision of better than 0.05 part per million has already been demonstrated in our lab.

G. Rajalakshmi and Pranav Shirhatti at TIFR Hyderabad have recently been awarded grant by i-HUB Quantum Technology Foundation) to be able to develop this promising design into a working prototype, ultimately leading towards a high-performance and cost-effective wavelength measuring device.

[1] A Multistage Thermal Drift Compensated Cross-Fringed Fizeau Interferometer Wavemeter and Method Thereof
Patent:  Indian App. No. 202321048766 dated 20-Jul-2023 – TIFR
Inventors: Saurabh Kumar Singh, Avinash Kumar and Pranav R. Shirhatti, TIFR, Hyderabad

Content: Pranav R. Shirhatti