Power control of a low noise CW Diode-Pumped Solid-State UV laser
Oxxius UV laser power control today
Presented at CLEO Europe 2007, this paper addresses CW DPSS UV laser power control, a critical requirement for 355 nm sources in intracavity frequency-tripled architectures, where pump current variations disrupt nonlinear conversion dynamics and introduce noise.. In intracavity frequency-tripled architectures, output power cannot simply be adjusted by varying pump current without disrupting the nonlinear conversion dynamics, a challenge that had limited the practical usability of early DPSS UV sources in sensitive analytical instruments.
The applications driving this work : wafer inspection, micromachining, flow cytometry, and cell sorting, all require not only low-noise output but also the ability to set and hold a specific power level reproducibly over time. The techniques described here contributed directly to making Oxxius’s 355 nm laser sources instrument-ready. Today, the LBX-355 and related UV sources in the Oxxius product line incorporate these power control capabilities as standard, enabling seamless integration into OEM and research systems alike.
Why power control matters in CW UV lasers
In a conventional diode laser or four-level DPSS system, output power can be adjusted by simply varying the pump diode current — the relationship between pump power and output is monotonic and well-behaved. In an intracavity frequency-tripled architecture at 355 nm, this simple approach fails: the nonlinear conversion efficiency depends on the intracavity power in a highly nonlinear way, and small changes in pump current produce disproportionate fluctuations in UV output. Active power control — using an independent attenuation or feedback mechanism — is therefore essential for instrument-grade usability.
The work presented here established the power control methodology that Oxxius subsequently implemented across its 355 nm UV laser product line, enabling reproducible power setting and long-term stability in analytical instruments where UV exposure dose must be precisely controlled. The LBX-355 incorporates these capabilities as standard today.
Abstract
Low noise CW Diode-Pumped Solid-State UV lasers are needed for many analytical applications in the semiconductor (wafer inspection, micromachining…) and biological fields (flow cytometry, cell sorting…). We have recently demonstrated that such laser sources can be obtained with Diode Pumped Solid States (DPSS) structures [1].