Publications

Results 101–148 of 148

Search results

Jump to search filters

Ultralow-loss silicon ring resonators

Optics Letters

Biberman, Aleksandr; Shaw, Michael J.; Timurdogan, Erman; Wright, Jeremy B.; Watts, Michael R.

We experimentally demonstrate silicon ring resonators with internal quality factors of Q0 = 2.2 × 107, corresponding to record 2.7 dB/m propagation losses. Importantly, we show that these propagation losses are limited by bend loss, indicating that the propagation loss limit for silicon has not yet been reached. © 2012 Optical Society of America.

More Details
TYPE Conference YEAR 2012
ScopusOSTI

Single-mode GaN nanowire lasers

Optics Express

Li, Qiming L.; Wright, Jeremy B.; Chow, Weng W.; Luk, Ting S.; Brener, Igal; Lester, Luke F.; Wang, George T.

We demonstrate stable, single-frequency output from single, asfabricated GaN nanowire lasers operating far above lasing threshold. Each laser is a linear, double-facet GaN nanowire functioning as gain medium and optical resonator, fabricated by a top-down technique that exploits a tunable dry etch plus anisotropic wet etch for precise control of the nanowire dimensions and high material gain. A single-mode linewidth of ∼0.12 nm and >18dB side-mode suppression ratio are measured. Numerical simulations indicate that single-mode lasing arises from strong mode competition and narrow gain bandwidth. © 2012 Optical Society of America.

More Details
TYPE Journal Article YEAR 2012
ScopusOSTIDOI

Top-down fabrication of GaN-based nanorod LEDs and lasers

Proceedings of SPIE - The International Society for Optical Engineering

Wang, George T.; Li, Qiming L.; Wierer, Jonathan J.; Figiel, Jeffrey J.; Wright, Jeremy B.; Luk, Ting S.; Brener, Igal

Although planar heterostructures dominate current optoelectronic architectures, 1D nanowires and nanorods have distinct and advantageous properties that may enable higher efficiency, longer wavelength, and cheaper devices. We have developed a top-down approach for fabricating ordered arrays of high quality GaN-based nanorods with controllable height, pitch and diameter. This approach avoids many of the limitations of bottom-up synthesis methods. In addition to GaN nanorods, the fabrication and characterization of both axial and radial-type GaN/InGaN nanorod LEDs have been achieved. The precise control over nanorod geometry achiveable by this technique also enables single-mode single nanowire lasing with linewidths of less than 0.1 nm and low lasing thresholds of ∼250kW/cm 2. © 2012 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

More Details
TYPE Conference YEAR 2012
OSTIScopus

Room temperature detector array technology for the terahertz to far-infrared

Shaner, Eric A.; Wright, Jeremy B.; Kadlec, Emil A.; Shaw, Michael; Lentine, Anthony L.; Rakich, Peter T.; Camacho, Ryan C.

Thermal detection has made extensive progress in the last 40 years, however, the speed and detectivity can still be improved. The advancement of silicon photonic microring resonators has made them intriguing for detection devices due to their small size and high quality factors. Implementing silicon photonic microring or microdisk resonators as a means of a thermal detector gives rise to higher speed and detectivity, as well as lower noise compared to conventional devices with electrical readouts. This LDRD effort explored the design and measurements of silicon photonic microdisk resonators used for thermal detection. The characteristic values, consisting of the thermal time constant ({tau} {approx} 2 ms) and noise equivalent power were measured and found to surpass the performance of the best microbolometers. Furthermore the detectivity was found to be D{sub {lambda}} = 2.47 x 10{sup 8} cm {center_dot} {radical}Hz/W at 10.6 {mu}m which is comparable to commercial detectors. Subsequent design modifications should increase the detectivity by another order of magnitude. Thermal detection in the terahertz (THz) remains underdeveloped, opening a door for new innovative technologies such as metamaterial enhanced detectors. This project also explored the use of metamaterials in conjunction with a cantilever design for detection in the THz region and demonstrated the use of metamaterials as custom thin film absorbers for thermal detection. While much work remains to integrate these technologies into a unified platform, the early stages of research show promising futures for use in thermal detection.

More Details
TYPE SAND Report YEAR 2011
DOIOSTI

Thermal Microphotonic Focal Plane Array (TM-FPA)

Shaw, Michael; Lentine, Anthony L.; Nielson, Gregory N.; Wright, Jeremy B.; Peters, David; Zortman, William; Mccormick, Frederick B.

The advent of high quality factor (Q) microphotonic-resonators has led to the demonstration of high-fidelity optical sensors of many physical phenomena (e.g. mechanical, chemical, and biological sensing) often with far better sensitivity than traditional techniques. Microphotonic-resonators also offer potential advantages as uncooled thermal detectors including significantly better noise performance, smaller pixel size, and faster response times than current thermal detectors. In particular, microphotonic thermal detectors do not suffer from Johnson noise in the sensor, offer far greater responsivity, and greater thermal isolation as they do not require metallic leads to the sensing element. Such advantages make the prospect of a microphotonic thermal imager highly attractive. Here, we introduce the microphotonic thermal detection technique, present the theoretical basis for the approach, discuss our progress on the development of this technology and consider future directions for thermal microphotonic imaging. Already we have demonstrated viability of device fabrication with the successful demonstration of a 20{micro}m pixel, and a scalable readout technique. Further, to date, we have achieved internal noise performance (NEP{sub Internal} < 1pW/{radical}Hz) in a 20{micro}m pixel thereby exceeding the noise performance of the best microbolometers while simultaneously demonstrating a thermal time constant ({tau} = 2ms) that is five times faster. In all, this results in an internal detectivity of D*{sub internal} = 2 x 10{sup 9}cm {center_dot} {radical}Hz/W, while roughly a factor of four better than the best uncooled commercial microbolometers, future demonstrations should enable another order of magnitude in sensitivity. While much work remains to achieve the level of maturity required for a deployable technology, already, microphotonic thermal detection has demonstrated considerable potential.

More Details
TYPE SAND Report YEAR 2009
DOIOSTI

Microphotonic thermal detectors and imagers

Proceedings of SPIE - The International Society for Optical Engineering

Shaw, Michael; Rakich, Peter T.; Lentine, Anthony L.; Nielson, Gregory N.; Wright, Jeremy B.; Zortman, William; Mccormick, Frederick B.

We present the theory of operation along with detailed device designs and initial experimental results of a new class of uncooled thermal detectors. The detectors, termed microphotonic thermal detectors, are based on the thermo-optic effect in high quality factor (Q) micrometer-scale optical resonators. Microphotonic thermal detectors do not suffer from Johnson noise, do not require metallic connections to the sensing element, do not suffer from charge trapping effects, and have responsivities orders of magnitude larger than microbolometer-based thermal detectors. For these reasons, microphotonic thermal detectors have the potential to reach thermal phonon noise limited performance. © 2009 SPIE.

More Details
TYPE Conference YEAR 2009
OSTIScopus
Results 101–148 of 148
Results 101–148 of 148