Trustees of the Colorado School of Mines

Km Labs Inc.

Charles G Durfee

Daniel E Adams

Sterling J Backus

Matthew S Kirchner

David Kleinfeld

Jeffrey Squier

Dawn Vitek

Thomas E Furtak

Reuben T Collins

Amanda K Meier

Jeff Squier

Spectral interferometric systems and methods to characterize lateral and angular spatial chirp to optimize intensity localization in spatio-temporally focused ultrafast beams are described. Interference between two spatially sheared beams in an interferometer leads to straight fringes if the wavefronts are curved. To produce reference fringes, one arm relative to another is delayed in order to measure fringe rotation in the spatially resolved spectral interferogram. Utilizing Fourier analysis, frequency-resolved divergence is obtained. In another arrangement, one beam relative to the other is spatially flipped, which allows the frequency-dependent beamlet direction (angular spatial chirp) to be measured. Blocking one beam shows the spatial variation of the beamlet position with frequency (i.e., the lateral spatial chirp).

Interferometer for spatial chirp characterization

Temporal focusing of spatially chirped femtosecond laser pulses overcomes previous limitations for ablating high aspect ratio features with low numerical aperture (NA) beams. Simultaneous spatial and temporal focusing reduces nonlinear interactions, such as self-focusing, prior to the focal plane so that deep (&#x2dc;1 mm) features with parallel sidewalls are ablated at high material removal rates.

Spatially chirped pulses for femtosecond laser ablation through transparent materials

Apparatus and methods for anisotropic pumping of a Kerr lens modelocked laser. Direct diode laser pumping of an ultrafast Kerr lens modelocked laser oscillator is accomplished. Diode lasers generate severely anisotropic beams, meaning the pump beam has a higher-beam-quality dimension and a lower-beam-quality dimension. By spatially overlap of the pump beam higher-beam-quality dimension and the KLM laser mode, KLM operation is accomplished. Multiple laser diode pump beams are combined in counterpropagating and same-side configurations.

Anisotropic beam pumping of a Kerr lens modelocked laser

This invention provides fundamental science and novel device architectures for surface plasmon (SP)-based, complementary metal oxide semiconductor (CMOS)-compatible, optical elements such as modulators, couplers, and switches. The primary focus of the work is on waveguides based on an ultra-long-range surface plasmon (ULRSP) waveguide mode recently discovered by our team. This mode exists at the metal-dielectric interfaces in a silicon-oxide-metal-silicon layer structure. While initial work focuses on noble metals to support the ULRSP, our analysis shows Si processing-compatible metals such as Cu and Al can also be used. Our modeling has also shown that variation in the thickness of the oxide layer can be used to give unprecedented propagation lengths in such structures. Electrically-induced free carrier modulation of the dielectric constant in the Si adjacent to the oxide can modulate the waveguide properties allowing novel Si-compatible electro-optic devices to be created. These waveguides function as the 'wiring' in new classes of optical chips. This invention also provides integration of ULRSP waveguides and switches with other optical elements to create entirely new classes of hybrid optoelectronic technologies for defense applications. These range from chip-based chemical agent detection to extremely high performance processors and even all-optical computations.

Silicon-compatible surface plasmon optical elements

Growing community of inventors

Golden, CO, United States of America

Charles G Durfee