05 January 2009 Blue Laser Highlighted in Optics&Laser Europe

Photograph of the green-pumped cw SRO based on MgO:sPPLT with internal frequency-doubling in BiB3O6, delivering tunable output beam in the blue.

Research by Prof. Ebrahim-Zadeh’s group on extended tunability of solid-state blue laser highlighted in the magazine. The October issue of Optics&Laser Europe (OLE) highlights the results of the latest research on an extensively tunable solid-state blue laser developed by Goutam Kumar Samanta (ICFO) and Prof. Majid Ebrahim-Zadeh (ICREA Professor at ICFO).

Blue lasers are relatively rare because of the shortage of laser crystals that can generate blue radiation. As such, there is a shortage of blue solid-state lasers compared to the other types of well-established lasers in the red and infrared. At the same time, blue laser light can offer important advantages for many applications. For example, due to shorter wavelength, it can be focused into smaller dimensions, providing the opportunity to perform operations on a smaller scale or conduct measurements to a higher degree of precision compared to lasers operating at longer wavelengths. These properties can be of great benefit to application fields as diverse as medical diagnostics, high-density data storage, high resolution spectroscopy, underwater communication, color displays and many other areas.

Although continuous-wave (cw) blue diode lasers are available, output power, beam quality, and tunability are limited. All other existing technologies developed to date suffer from the common drawback of limited or no tunability, low power and high cost. The highlight in OLE reports on a paper published in the June issue of Optics Letters, where ICFO and ICREA researchers describe a compact solid-state blue laser that offers practical output power, single-mode operation and a wide tuning range, using a new method based on second-harmonic generation inside the cavity of a green-laser-pumped cw singly-resonant optical parametric oscillator (SRO).

“Using this new technique, our goal is to develop a new generation of widely tunable laser sources for the blue-green spectrum in compact and practical design that can provide cw, single-mode radiation at watt-level output power with high stability and fine-frequency tuning capability”, Goutam Kumar Samanta and Majid Ebrahim-Zadeh said. “Such a source would readily find its application not only in laser display technology and medical diagnostics, but in underwater communication, data storage, and basic photonic research.”