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Department of Physics

Brian Washburn

Brian WashburnAssociate Professor
36C Cardwell Hall
(785) 532-2263
Personal Webpage

Ph.D. Georgia Institute of Technology, 2002
B.S. University of Wisconsin - Parkside, 1994

Research Area

My research falls within the intersection of nonlinear fiber optics, laser physics, and photonic crystal technology. My group has two main research endeavors: one project on fiber laser based frequency combs, and one project on gas-filled hollow core photonic crystal fiber (HC-PCF) lasers.

My research group has made significant contributions to fiber based infrared frequency combs, which can be used as a robust and portable system for precision spectroscopy.  We have phase-stabilized, for the first time, a fiber laser that uses carbon nanotubes for a saturable absorber.  The carbon nanotube fiber laser frequency comb offers much promise as a portable, robust, and inexpensive fiber frequency comb with further potential for scaling to higher repetition frequencies.  We performed careful measurements to measure the fractional stability of this comb and compared it with combs in our laboratory.

Recently, we have made progress developing mode-locked Tm doped fiber lasers. The goal of this project is to extend phase stabilized fiber combs into the mid-IR. We have developed and demonstrated a self-starting, passively mode-locked Tm/Ho co-doped fiber laser that lases at one of two center wavelengths. We have also have demonstrated stretch-pulse operation of a Tm doped fiber laser in an all fiber format.

Dr. Kristan Corwin and I are part of a collaborative program to develop molecular gas-filled hollow optical fiber lasers.   We demonstrated what we believe is the first optically pumped gas laser based on population inversion in a hollow core photonic crystal fiber.  The laser produces mid-IR (3.1-3.2 μm) lasing by optically pumping with 1.5 μm, nanosecond pulses.  We are in the process of making a similar molecular gas which will have lower lasing threshold.

Research Support


Recent Selected Publications

R. Kadel and B. R. Washburn, "All-fiber passively mode-locked thulium/holmium laser with two center wavelengths", , ◦Applied Optics, Vol. 51 Issue 27, pp.6465-6470 (2012). [link]

Nampoothiri, A V Vasudevan; Jones, Andrew M; Fourcade-Dutin, C; Mao, Chenchen; Dadashzadeh, Neda; Baumgart, Bastian; Wang, Y Y; Alharbi, M; Bradley, T; Campbell, Neil; Benabid, F; Washburn, Brian R; Corwin, Kristan L; Rudolph, Wolfgang, "Hollow-core Optical Fiber Gas Lasers (HOFGLAS): a review:", Optical Materials Express, Vol. 2, Issue 7, pp. 948-961 (2012). [link]

M. Jones, A. V. V. Nampoothiri, A. Ratanavis, T. Fiedler, N. V. Wheeler, F. Couny, R. Kadel, F. Benabid, B. R. Washburn, K. L. Corwin and W. Rudolph, "Mid-infrared gas filled photonic crystal fiber laser based on population inversion", Optics Express Vol. 19 Issue 3, pp.2309-2316 (2011). [link]

K. Knabe, S. Wu, J. Lim, K. A. Tillman, P. S. Light, Fr. Couny, N. Wheeler, R. Thapa, A. M. Jones, J. W. Nicholson, B. R. Washburn, F. Benabid, and K. L. Corwin, "10 kHz accuracy of an optical frequency reference based on 12C2H2 filled large-core kagome photonic crystal fibers", Opt. Express 17, 18, pp. 16017–16026 (2009).  [link]

J. Lim, K. Knabe, K. A. Tillman, W. Neely, Y. Wang, R. Amezcua-Correa, F. Couny, P. S. Light, F. Benabid, J. C. Knight, K. L. Corwin, J. W. Nicholson, and B. R. Washburn, A phase-stabilized carbon nanotube fiber laser frequency comb, Opt. Express 17, 14115-14120 (2009). [link]