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A new method of dispersion engineering for crystalline resonators

January 30th, 2015

WPBRe have developed a method to engineer dispersion of crystalline resonators for the first time. This was possible with help of a novel resonator design, a “Photonic Belt Resonator” (PBR). The mode frequencies of such a resonator can be fine-tuned by changing the shape of the belt. We demonstrate striking enhancement of Kerr comb bandwidth generated in the new PBRs. The results are published in Optica


Continuous tuning of double resonance in whispering gallery mode resonator

January 28th, 2014

1A method has been demonstrated for continuous tuning of double resonance-enhanced ultraviolet (UV) radiation of second harmonic generation in a dispersive beta barium borate (BBO) whispering gallery mode resonator. The tuning method is described in a recently published paper in Opt. Express. A patent is is pending for the tuning method as well.

Old tricks for new applications

December 3rd, 2013

exoStellar intensity interferometer is proposed for observation of exoplanets and other dark space objects. Inspired by quantum ghost imaging and funded by NASA NIAC program, we have carried out an investigation of using star light and intensity interferometer technique to observe space objects such as exoplanets. The study addresses a novel aspect of stellar intensity interferometry, namely, the possibility to observe and characterize dark objects using distortions they impart on spatial coherence of thermal light sources. The initial results of the studied are now published in Physical Review A 88, 053837 (2013)

New phase matching method in micro resonators for wide-range efficient nonlinear frequency conversion

October 31st, 2013

ScreenHunter_02 Nov. 06 15.39A wide-range efficient method for optical second harmonic generation based on a whispering gallery mode resonator made from crystalline beta barium borate has been reported. With a single BBO resonator, efficient second harmonic generation has been demonstrated over one octave wavelength range. The paper appears in Appl. Phys. Lett.

Better understanding of microcombs is achieved

October 29th, 2013

A paper “Impact of cavity spectrum on span in microresonator frequency combs” by Ivan Grudinin, Lukas Baumgartel, and Nan Yu is published in Optics Express.  Mode crossings, total cavity dispersion and Raman lasing are studied as they determine the behavior of microcombs.

Ghost imaging to search for space objects

February 22nd, 2013

We are exploring the application of ghost-imaging-like techniques to astronomy, with the objective of detecting intensity-correlation signatures resulting from space objects of interest, such as exo-planets, gas clouds, and gravitational lenses. We show that the key aspect of being able to utilize ghost imaging in astronomy is the recognition that in interstellar imaging geometries the object of interest can act as an effective beam splitter, yielding detectable variations in the intensity-correlation signature. Some of the recent findings are summarized in Journal of Physics: Conference Series 414 (2013) 012037

Micro-fabrication augmented whispering gallery mode resonators open up new possibilities

January 16th, 2013

We apply focused ion beam (FIB) methods to precisely engrave a surface grating directly into the perimeter of a crystalline disc. The grating provides a simple and highly directional free-space coupling mechanism with superior stability to evanescent coupling techniques. These embedded gratings can also provide control of the resonance spectrum, significantly reducing the mode density. Other augmentations and applications are possible. The research results are reported in the forthcoming issue of Optics Letters

Smallest trapped ion clock physics package demonstrated

December 28th, 2012

In collaboration with Sandia National Laboratory in a joint DARPA project, JPL has developed a 3 cc trapped ion package. The Yb+ ion clock package is completed sealed off without any active pump yet provide exceptionally long long trapping lifetime. Using this small package, the Sandia team was able to demonstrate the fractional frequency stability at the level of 10^-14 range after a few days of integration. The results have been reported in Applied Physics Letters

Optical frequency reference using small whispering gallery mode resonators stabilized with a dual mode scheme

December 28th, 2012

A small temperature-stabilized WGM resonator has been shown to have an equivalent temperature coefficient of less than 40 ppb, close to that of ULE. We utilize the dual mode scheme for the resonator temperature stabilization. IN addition, we investigated potentials and limitations of the dual mode scheme in frequency stabilization. In the experiment, we demonstrated a 1560 nm laser stabilized to 1.3×10^-12 at 1 s and a long term drift of 21 kHz/hr over one day period. The result has been published in the most recent Optics Express

Towards the coldest spot in the Universe

December 28th, 2012

NASA has recently begun development on the Cold Atom Laboratory (CAL), a multi-user facility for the study of ultra-cold quantum gases in the microgravity environment of the space station. One of the primary goals of this facility will be to explore a previously inaccessible regime of extremely low temperatures where interesting and novel quantum phenomena can be expected. It will also be a pathfinder experiments for many cold atom based space applications to come in the future. JPL will be responsible for developing the CAL ISS payload. The Quantum Sciences and Technology group will be a key player in the ISS facility development as well as science experiments. For more information, please visit CAL website

Low-threshold solid-state 280 nm UV laser demonstrated.

December 12th, 2012

A low-threshold solid-state UV laser using a whispering gallery mode resonator is demonstrated. Using a Ce3:LiCaAlF6 resonator, we observe broad bandwidth lasing (280–330 nm) with a low threshold intensity of 7.5 × 109 W∕m2 and an effective slope efficiency of ~25%. The combination of this high Q and the small WGM mode volume significantly lowers the pump power threshold compared to traditional cavity designs, opening the door for both tunable continuous-wave and mode-locked operation. The results are published in Optics Express.

FEM analysis of coupled microdisk resonators

October 3rd, 2012

Finite element analysis of two vertically coupled microdisk resonators for displacement and acceleration sensing is carried out and published in JOSA B. The paper uses a publicly available solver and provides a script for the whispering gallery mode eigenvalue problem.

Most efficient cold atom source yet

September 25th, 2012

We have demonstrated another version of compact high-efficiency slow atom beam source based on a retro-reflected two-dimensional magneto-optical trap.  Employing two laser beams in an angled retro-reflected setup, we achieve  3D MOT loading rates nearly 1×1010 atoms/s using only 20 mW of total laser power for the source. The work is published in Applied Physics B, Laser and Optics .

First high-Q UV whispering gallery mode resonators with a twist

September 5th, 2012

We have demonstrated for the first time the high Q WGM resonators in the UV region. The cavities are  made from angle-cut BBO crystals. This work will help to push WGM resonator applications in the UV region. The non z-cut resonators exhibit interesting polarization rotation of WGMs and may lead to novel nonlinear  optical applications. These results are published in the forthcoming page of Optics Express.

New open whispering gallery mode resonator structures

August 2nd, 2012

July 30th, 2012. The first completely open WGM resonator has been demonstrated using focused ion beam (FIB) microfabrication techniques. This open WGM structure provides total access to the whispering gallery modes, and will find applications in optomechanical and chemical sensors. The results have been published in the latest issue of Optics Express

DSAC mission news

May 1st, 2012

Deep space GPS will benefit from the work done in our group. Read more news on the Deep Space Atomic Clock and the mission highlights at this NASA website.

Micro resonator research image appears at the home page of American Physical Society

April 26th, 2012
Micro resonator research image appears at the home page of American Physical Society. 
A direct link to the image can be found at The image shows a focused ion beam (FIB) engineered disc resonator under test, which has an open cavity structure, i.e., a milled notch dissects the resonator disc and creates a free space gap within the mode volume. This novel approach allows direct access to the full circulating field inside the resonator. The FIB technology also opens the door for other functional features to be formed in the dielectric resonator structures.

Microresonator frequency comb

March 6th, 2012

Our contribution titled “Frequency comb from a microresonator with engineered spectrum” is published in Optics Express. We have achieved generation of a comb spanning over 200 nm with only 50 mW pump.

Group site is live

February 18th, 2012

Our group website is now hosted and is available for all

NASA Technology Demonstration

November 15th, 2011

Liter-sized Space Clock development helped to win a NASA Technology Demonstration Mission.
The SOMD SCaN (office 970) mercury ion atomic clock development concluded last week following the start-up of the OCT Technology Demonstration Mission (TDM) task. The 970 effort significantly advanced ion clock technology over a 5+ year development period, indeed, enabling the successful proposal to the recent OCT TDM call. During this time, a small breadboard prototype physics package was developed to demonstrate a few liter atomic ion clock far exceeding performance of current day space clocks developed under GPS, GALILEO, and GLONASS programs.


The JPL ion clock technology integrated ion traps, ultra-violet optical systems, mm microwave injection, high stability magnetic coils and shields, and a novel vacuum tube, fabricated from high temperature tolerant materials to remove cumbersome active vacuum pumps from the instrument package. The vacuum tube approach enables reliable long-term clock operation by eliminating consumables that limit lifetime of other space clock instruments.
The SOMD/SCaN organization continues to support the DSAC (Deep Space Atomic Clock) OCT Technology Demonstration Mission (TDM) through a 26% cost infusion over the period of execution of the TDM Mission.


A reimbursable program, also based on the SOMD/SCaN/JPL ion clock technology, was funded by Lockheed-Martin for infusion of the JPL ion clock into the GPS constellation as an upgrade to the present day GPS Rubidium/Cesium clocks. This effort was in collaboration with technology transfer partner Symmetricom (Beverly, MA) and funded by Lockheed-Martin, the prime contractor for GPS III navigation system




November 10th, 2011

Our group has won 2 NASA OCT CIF awards. The tasks are “Nanofabricated Optomechanical Whispering Gallery Mode Resonators for Acceleration and Gyroscopic Sensors” and “Nonlinear Optical Terahertz Technology”




November 1st, 2011

Work on laser stabilization with WGM resonators was published in Optics Express.


New group website

November 1st, 2011

The group website was renewed.