Development of a deep-ultraviolet pulse laser source operating at 234 nm for direct cooling of Al⁺ ion clocks

Abstract

We report on the development of a 250-MHz 234 nm deep-ultraviolet pulse source based on a flexible wavelength-conversion scheme. The scheme is based on a frequency-doubled optical parametric oscillator (FD-OPO) together with a cascaded frequency conversion process. We use a χ(2) nonlinear envelope equation to guide the design of an intra-cavity OPO crystal, demonstrating a flexible broadband tunable feature and providing as high as watt-level of a frequency-doubled signal output centered at 850 nm, which is served as an input wave for the cascaded frequency conversion process. As much as 3.0 mW of an average power at 234 nm is obtained, with an rms power stability of better than 1% over 20 minutes. This deep-ultraviolet pulse laser source can be used for many applications in quantum optics and for direct laser cooling of Al+ ion clocks.

Reflective Spiral Phase Converter: A New Route to Ultrafast Singular Optics

“…The generation of ultraviolet (UV) femtoseconds pulses is attracting recent attention due to several potentials applications such as surface structuring [41], micromachining [42], remote sensing [43], spectroscopy and imaging [44]. Due to this potential, despite being complicated to generate sub-10-fs pulses because of the large dispersion in transparent media in this wavelength range, several schemes have been developed using second-order [45] as well as third-order non linear effects [46].…”

Design of quasi-phase-matching nonlinear crystals based on quantum computing

“…We chose CTHG of 1404 nm light to 468 nm as an example to verify the proposed APPLN design method. This CTHG process was proposed to be a part of a scheme of 234 nm deep UV generation (Figure 3) for Al + cooling [2].…”

“…However, research in fields such as spectroscopy often requires wavelengths from the deep ultraviolet to the mid-infrared from a laser system as simple and efficient as possible. For example, currently there is no mature technology to obtain ultrashort 234 nm optical pulses directly from a laser for Al + cooling in an optical clock [2]. Therefore, nonlinear frequency conversion is an important technique to obtain lights at various wavelengths flexibly.…”

GPU-Accelerated Full-Field Modelling of Highly Dispersive Ultrafast Optical Parametric Oscillators

“…We have previously demonstrated [9] that the NEE provides good agreement with OPOs containing short (≤ 1 mm) nonlinear crystals operating in a low-dispersion regime [10][11][12], however dispersive OPO cavities such as those containing long crystals [13][14][15] or significant material dispersion [16][17][18][19] result in fields exhibiting large computational time-bandwidth products, requiring a simulation that comprises both large temporal and spectral ranges. Modelling such fields is computationally expensive due to the data required to maintain sufficient sampling in large temporal/spectral windows (space complexity), compounded by the many round-trips needed to achieve steady-state (time complexity), an issue not encountered when simulating single-pass nonlinear frequency conversion processes [20].…”