Long-term stabilization of the length of an optical reference cavity

We successfully stabilized a Fabry-P\'erot optical cavity incorporating a bulk diamond crystal at millikelvin temperatures in a cryogen-free dilution refrigerator with the pulse-tube cryocooler running. In stark contrast to previous demonstrations where lasers were locked to the cavities, our setup locks the cavity to a laser. Our measurements of cavity length fluctuation suggest that the setup could stabilize a cavity up to a finesse of $1.2\times 10^4$ without the diamond a...

This paper considers the application of integral Linear Quadratic Gaussian (LQG) optimal control theory to a problem of cavity locking in quantum optics. The cavity locking problem involves controlling the error between the laser frequency and the resonant frequency of the cavity. A model for the cavity system, which comprises a piezo-electric actuator and an optical cavity is experimentally determined using a subspace identification method. An LQG controller which includes i...

We present an experimental technique allowing to stabilize the frequency of the non resonant wave in a singly resonant optical parametric oscillator (SRO) down to the kHz level, much below the pump frequency noise level. By comparing the frequency of the non resonant wave with a reference cavity, the pump frequency noise is imposed to the frequency of the resonant wave, and is thus subtracted from the frequency of the non resonant wave. This permits the non resonant wave obta...

We describe an optical frequency stabilization scheme of a microwave oscillator that is used for the interrogation of primary caesium fountain clocks. Because of its superior phase noise properties, this scheme, which is based on an ultrastable laser and a femtosecond laser frequency comb, overcomes the frequency instability limitations of fountain clocks given by the previously utilized quartz-oscillator-based frequency synthesis. The presented scheme combines the transfer o...

Highly coherent optical sources are a key element in several fields of physics, in particular in time frequency metrology. Over the past decennia, there has been particular efforts in developing such sources to the expense of sophisticated laser systems and relatively smart electronics. We propose here a new general principle of a self-adaptive oscillator where the intricate operation of a 100-m-long active optical resonator and a standard semiconductor laser offers a very hi...

We develop and demonstrate a compact (less than $6$ mL) portable Fabry-P\'{e}rot optical reference cavity. A laser locked to the cavity is thermal noise limited at $2\times10^{-14}$ fractional frequency stability. Broadband feedback control with an electro-optic modulator enables near thermal-noise-limited phase noise performance from $1$ Hz to $10$ kHz offset frequencies. The additional low vibration, temperature, and holding force sensitivity of our design makes it well sui...

Large ring lasers employed in geodesy and fundamental physics require stability of the perimeter at or below the parts-per-billion level. We present two complementary approaches to actively control the perimeter length of such ring lasers, reaching a relative length stability of $4\times 10^{-10}$. These methods can readily be implemented and bring the stability of heterolithic devices on par with monolithic designs.

We propose a dual cavity Fabry-Perot interferometer as a wavelength calibrator and a stability tracking device for astronomical spectrograph. The FPI consists of two adjoining cavities engraved on a low expansion monoblock spacer. A low-finesse astro-cavity is intended for generating a uniform grid of reference lines to calibrate the spectrograph and a high-finesse lock-cavity is meant for tracking the stability of the reference lines using optical frequency standards. The di...

The residual cavity-pulling effect limits further narrowing of linewidth in dual-wavelength (DW) good-bad-cavity active optical clocks (AOCs). In this paper, we for the first time experimentally realize the cavity-length stabilization of the 1064/1470 nm DW-AOCs by utilizing the phase locking technique of two independent 1064 nm good-cavity lasers. The frequency tracking accuracy between the two main-cavities of DW-AOCs is better than $3 \times {10^{ - 16}}$ at 1 s, and can r...

Continuously and widely tunable lasers actively stabilized on a frequency reference are broadly employed in atomic, molecular and optical (AMO) physics. The frequency-stabilized optical frequency comb (OFC) provides a novel optical frequency reference with a broadband spectrum that meets the requirement of laser frequency stabilization. Therefore, we demonstrate a frequency-stabilized and precisely tunable laser system based on it. In this scheme, the laser frequency locked t...