Accurate relative frequency cancellation between two independent lasers

Abstract

For high-precision frequency-based applications of lasers, the frequency difference between two independent lasers is accurately stabilized and maintained. We describe a simple and novel feed-forward method with an acousto-optic modulator. This method can be used in optical phase-locked loops.

Ultraslow Propagation of Squeezed Vacuum Pulses with Electromagnetically Induced Transparency

“…The beam from the other Ti:sapphire laser (labeled Ti:S laser 2) was diffracted by an acousto-optical modulator (AOM) 1 and was used for the control field. The frequency of the control light was stabilized using a feed-forward method [9], and the control light was able to be scanned around the F 2 ! F 0 2 transition by tuning the frequency of a synthesizer.…”

Experimental considerations on bandwidth measurement of ultra-fast photoreceptors by optical heterodyning

“…Expression of I ph given by (8) means that the signal achieved by optical heterodyne is composed of CW component and another component at the beat frequency Dm = jm 1 À m 2 j, difference in frequency of the two lasers. When considering the correspondence between optical frequency and wavelength for an optical wave, we can note…”

“…Considering (8), the term / 1 (t) À / 2 (t) means that the phase noise of the RF signal I ph is dependant on the two phase noises of the two lasers. This phase noise leads to an widening of the ray representing the power spectral density of the electric signal generated by the photoreceptor and measured with the RF spectrum analyzer.…”

“…However, there is a limitation on the achievable bandwidth to a few gigahertz due to the locking technique. OPLL set-up is suitable in the case of high stability beat signals required [8,9]. On the contrary, two independent laser sources provide a modulated signal on a wide frequency range (far beyond 40 GHz), suited for very fast photodiodes bandwidth characterisation.…”

Quantum memory of a squeezed vacuum for arbitrary frequency sidebands

“…Here, Ti:sapphire laser 1 was used to generate and detect the squeezed vacuum, the carrier frequency of which was resonant on the 5 2 S 1/2 , F = 1 → 5 2 P 1/2 , F = 2 transition, and Ti:sapphire laser 2 was diffracted by an acousto-optic modulator (AOM) and was used as the control light. The relative frequency between the probe light and the control light was stabilized using the feed-forward method [15]. By adjusting the frequency of the synthesizer, the detuning of the control light could be precisely controlled around the 5 2 S 1/2 , F = 2 → 5 2 P 1/2 , F = 2 transition.…”