Related papers: Measuring the speed of light using beating longitu…
We empirically determined the speed of light by measuring the variation in longitudinal mode frequencies, or the beat frequencies, of an adjustable-length, open-cavity helium-neon laser as a function of its cavity length. The TEM$_{00}$…
A novel method capable of delivering relative optical path length metrology with nanometer precision is demonstrated. Unlike conventional dual-wavelength metrology which employs heterodyne detection, the method developed in this work…
Length and g-factor are fundamental parameters that characterize optical cavities. We developed a technique to measure these parameters in-situ by determining the frequency spacing between the resonances of fundamental and spatial modes of…
We describe a technique for measuring the complex reflectivity of an optical cavity with a resonant local oscillator laser and an auxiliary probe laser, each coupled via opposite ends of the cavity. A heterodyne sensing scheme is then used…
Tunable lasers are essential for optical communication, spectroscopy, and precision sensing, where flexible and fast control of the laser wavelength is needed. However, conventional tunable laser systems often rely on mechanical actuation,…
From the standard TEM00 Gaussian beam profile equations, we have derived the equations for beam waist at lens focus as a function of variable spot size. In this process, we obtained two equations for beam waist and the validity of these…
Laser interferometry is an extensively used diagnostic for plasma experiments. Existing plasma interferometers are designed on the presumption that the scene and reference beam path lengths have to be equal, a requirement that is costly in…
We present a modified approach to laser optical-feedback cavity-enhanced absorption spectroscopy. The technique involves continuously scanning the length of a high-finesse cavity to periodically lock a diode laser to the cavity resonance,…
We propose a novel scheme for accurately determining hundred-hertz linewidth by delayed self-heterodyne method in which delay time far less than the laser's coherence time. That exceeds the former understanding as to the delayed…
We report on a high-resolution double-channel imaging method used to synchronously map the intensity- and optical-frequency-distribution of a laser beam in the plane orthogonal to the propagation direction. The synchronous measurement…
Advances in high-resolution laser spectroscopy have enabled many scientific breakthroughs in physics, chemistry, biology and astronomy. Optical frequency combs have pushed measurement limits with ultrahigh-frequency accuracy and…
State-of-the-art laser frequency stabilization is limited by miniscule length changes caused by thermal noise. In this work, a cavity-length-insensitive frequency stabilization scheme is implemented using strong dispersion in a…
The invariance of the speed of light in the distant universe has profound significance for fundamental physics. In this paper, we propose a new model-independent method to test the invariance of the speed of light $c$ at different redshifts…
A study of Helium-Neon laser plasma lines was done using a double grating spectrometer and a He-Ne laser with an emission wavelength of 632.8 nm (15,802 cm$^{-1}$). The absolute wavenumber, measured to within $\sim0.1$ cm$^{-1}$, and…
Measuring low light absorption with combined uncertainty < 1 permille is crucial in a wide range of applications. Popular cavity ring-down spectroscopy can provide ultra-high precision, below 0.01 permille, but its accuracy is strongly…
A powerful test of fundamental physics consists on probing the variability of fundamental constants in Nature. Although they have been measured on Earth laboratories and in our Solar neighbourhood with extremely high precision, it is…
An experimental study of the delayed threshold phenomenon in a Vertical Extended Cavity Semiconductor Emitting Laser is carried out. Under modulation of the pump power, the laser intensity exhibits a hysteresis behavior in the vicinity of…
Probing the speed of light is as an important test of General Relativity but the measurements of $c$ using objects in the distant universe have been almost completely unexplored. In this letter, we propose an idea to use the multiple…
The possible time variation of the fundamental constants of nature has been an active subject of research in modern physics. In this paper, we propose a new method to investigate such possible time variation of the speed of light $c$ using…
An experimental scheme is introduced to measure multiple parameters that are encoded in the phase quadrature of a light beam. Using a modal description and a spectrally-resolved homodyne detection, it is shown that all of the information is…