The University of St.Andrews Microchip Laser Research Group

School of Physics and Astronomy at St Andrews

Dr David Matthews working on a blue microchip laser.

 

What is a Microchip Laser?

The microchip or cube laser in its modern form was first proposed by Zayhowski & Mooradian and by Dixon, both in 1989. A diode laser is used to excite a thin (typically sub-millimetre) slice of solid state gain material, onto which dielectric coatings have been deposited. This very short and simple laser can be inherently single frequency, as the spacing between longitudinal modes is so large. The short cavity lifetime is useful for the generation of short (sub nanosecond) pulses. The design is robust and stable, and amenable to mass production techniques. There is some interesting physics regarding the operation of these devices, especially the formation of a high-quality TEMoo laser beam from what would appear to be a laser oscillator on the verge of cavity stability. With addition of other components, this new laser type can be made even more versatile. A short review of microchip lasers is available.

We have worked on intracavity frequency-doubled versions of these devices to produce green, red, and blue lasers. In this case a slice of nonlinear material is included in the sandwich between the cavity reflectors. The circulating field at 1340, 1064, or 946 nm builds up to a very high level, allowing efficient harmonic generation.

 

Passive Q-switching techniques allow the generation of short pulses. We have worked with the International Laser Centre in Belarus to demonstrate this technique at 1342 nm.

Active Q-switching techniques in small lasers have the same advantages, but can also allow the generation of pulses on demand. As part of a EPSRC/DTI Link scheme we worked on developing actively Q-switched lasers for undersea vision systems.

Underlying this activity are investigations into the basic science of these devices.

Commercial Achievements

Our green microchip laser, licensed by our University to Uniphase, won the "Laser Focus" Commercial Achievement Award 1995, and similar awards from Photonics Spectra and Lasers and Optronics.

 

 

 

Some of Our Microchip Laser Publications

N MacKinnon and B D Sinclair, "Pump power induced stability in lithium neodymium tetraphosphate (LNP) lasers", Optics Commun. 94 (15 November 1992) 281 - 288.

N MacKinnon and B D Sinclair, "A laser diode array pumped, Nd:YVO4/KTP composite material microchip laser", Optics Commun. 105 (February 1994) 183 - 187.

N MacKinnon, C J Norrie, and B D Sinclair, "Laser diode pumped, electro-optically tunable Nd:MgO:LiNbO3 microchip laser", J. Opt. Soc. Am. B 11 (March 1994) 519 - 522

D G Matthews, R S Conroy, B D Sinclair, and N MacKinnon,, "Blue microchip laser fabricated from Nd:YAG and KNbO3", Optics Letters 21 (February 1, 1996) 198 - 200.

D. G. Matthews, J. R. Boon, R. S. Conroy and B. D. Sinclair "A comparative study of diode pumped microchip laser materials: Nd-doped YVO4, YOS, SFAP, and SVAP", J. Mod. Opt. 43 (May 1996) 1079 - 1087.

R S Conroy, A J Kemp, G J Friel, and B D Sinclair, Microchip Nd:vanadate lasers at 1342 and 671 nm, Optics Letters, 1997, Vol.22, No.23, pp.1781-1783

G.J. Friel, R.S. Conroy, A.J. Kemp, B.D. Sinclair, J.M. Ley:, Q-switching of a diode-pumped Nd:YVO4 laser using a quadrupole electro-optic deflector, Appl Phys B 67 (1998), 267

R S Conroy, C F Rae, G J Friel, M H Dunn, B D Sinclair, J M Ley , Compact low-threshold Q-switched intracavity optical parametric oscillator, Optics Letters 23, (1998), 1348

A M Malyarevich, I A Denisov, K V Yumashev, V P Mikhailov, R S Conroy, and B D Sinclair , V:YAG - a new passive Q-switch for diode-pumped solid-state lasers, Applied Physics B-Lasers and Optics 67 (1998), 555

R S Conroy, T Lake, G J Friel, A J Kemp, and B D Sinclair, Self-Q-switched Nd:YVO4 microchip lasers, Optics Letters 23 (1998) 457

G M Gibson, R S Conroy, A J Kemp, B D Sinclair, M J Padgett, and M H Dunn, Microchip laser-pumped continuous-wave doubly resonant optical parametric oscillator, Optics Letters 23 (1998) 517.

B D Sinclair, Frequency Doubled Microchip Lasers, J. Opt. Mat. 11 (1999) 217

A J Kemp, R S Conroy, G J Friel, and B D Sinclair, Guiding effects in Nd:YVO4 microchip lasers operating well above threshold, IEEE J. Quantum Electron. 35 (1999) 675

Current team members are Tanya Lake and Bruce Sinclair.
Members who have moved on are Neil MacKinnon (now at Uniphase), David Matthews (now at Light Solutions),  Richard Conroy (now in Germany), Alan Kemp (now in St Andrews), and Graham Friel (now at Heriot-Watt University)


We are pleased to acknowledge support for our activities currently and/or in the past from

 

For more information please contact Bruce Sinclair at the School of Physics and Astronomy, University of St Andrews, St Andrews, Fife, Scotland, KY16 9SS, email b.d.sinclair@st-andrews.ac.uk

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