1.064 µm CW stable single frequency emission and low noise reduction based on a monolithic cavity

Oxxius 1064 nm single-frequency lasers today

Published at SPIE Photonics West 2021, this paper presents the development of a compact, low-noise single-frequency source at 1064 nm based on a linear monolithic cavity — an architecture that Oxxius has refined across its standard product line. The approach addresses a fundamental challenge in precision metrology: combining narrow linewidth, high frequency stability, and low relative intensity noise in a format compact enough for field-deployable instrumentation.

The applications driving this work — laser locking and seeding, atom cooling and trapping, optical heterodyning, and coherent communications — all demand a level of spectral purity that conventional multi-longitudinal-mode sources cannot provide. The double Lyot filter configuration described here enables reliable single-mode selection without the mechanical complexity of ring cavity geometries.

This research directly underpins the LCX-1064S, Oxxius’ production single-frequency laser at 1064 nm, which delivers the same monolithic cavity stability in a compact, turn-key module suited for integration into scientific instruments and OEM systems.

Why single-frequency emission at 1064 nm matters

Single-frequency operation at 1064 nm is one of the most demanding specifications in solid-state laser design. Unlike multi-longitudinal-mode sources, a single-frequency laser emits in a single, stable spectral line — with linewidths that can reach below 1 kHz in optimized configurations. This level of coherence is essential wherever the laser wavelength itself carries information: interferometric sensing, heterodyne detection, gravitational wave instrumentation, and optical frequency standards all rely on it.

The conventional solution for single-frequency emission at 1064 nm has long been the Non-Planar Ring Oscillator (NPRO), a monolithic Nd:YAG geometry that suppresses spatial hole burning through its unidirectional ring topology. While highly effective, NPRO architectures require precision manufacturing and are difficult to miniaturize. The linear monolithic cavity approach presented in this paper achieves comparable spectral purity through a double Lyot filter scheme — selecting first the emission band, then the single longitudinal mode — in a geometry that is inherently more compact and manufacturable at scale.

Performance and integration

The 500 mW output level demonstrated here places this source in a range directly usable for seeding high-power amplifier chains, optical trapping experiments, and coherent LIDAR systems without additional amplification stages. The low relative intensity noise (RIN) performance, achieved through careful cavity design rather than active stabilization, simplifies integration into OEM instruments where additional electronics represent both cost and reliability concerns.

Oxxius’s Single Frequency Laser product line translates this research into production-ready modules, available with free-space or fiber-coupled output, and compatible with standard OEM integration formats. The LCX series at 1064 nm delivers the monolithic cavity stability demonstrated in this paper in a turn-key package qualified for continuous operation in scientific and industrial environments.

The 1064 nm single-frequency monolithic laser remains one of the most requested wavelengths in Oxxius’s product portfolio, reflecting the breadth of precision applications that depend on narrow-linewidth, low-noise infrared emission.