Skip to Local Navigation
Skip to Content
California State University, Long Beach
Print this pageAdd this page to your favoritesSelect a font sizeSelect a small fontSelect a medium fontSelect a large font
Department News and Colloquium

Physics & Astronomy Colloquium at CSU Long Beach


What is a Sagnac interferometer and what can it do?

Jing Xia,
UC Irvine.

Monday, March 9, 2015
11:15am, PH2-110
(Refreshments served at 10:45am in HSCI-224)

Fig: A scanning Sagnac microscope

Symmetry is central to our understanding and description of natural phenomena. For example, conventional superconductors break only gauge symmetry, while a signature of an unconventional superconducting state is the breaking of additional symmetries. The breaking of time-reversal symmetry (TRS) is of particular interest since the condensate will have an overall magnetic moment due to either the spin or orbital (or both) parts of the pair wave function. To this end we have developed an optical technique for detecting broken TRS using a Sagnac interferometer, in which left and right circularly polarized lights propagate in opposite directions in the Sagnac loop and interact with the sample. The two lights, being time-reversal mirror image of each other, will gain a difference in phase due to broken TRS in the sample. And the achieved resolution is an unappreciated 10 nano radian at DC. In this talk, I will describe a few results we obtained with this Sagnac technique: (1) We used the Sagnac interferometer to identify TRS breaking in p-wave superconductor Sr2RuO4 across the superconducting transition; (2) We have identified in high temperature superconductors YBCO and LBCO broken TRS at temperatures tracking the so-called "Pseudo Gap" phase; (3) We have discovered that the ferromagnetism in ultra-thin perovskite films can be tuned with a patternable capping layer; (4) We are developing a functional brain imaging system based on Sagnac technology.

See the colloquium schedule and its archive of previous talks

Colloquia are scheduled to start Mondays at 11:15am sharp in Peterson Hall 2, Room 110 (PH2-110, map). Refreshments are served from 10:45am to 11:05am in Room HSCI-224 (next to the department office) and everyone is invited to mingle with faculty and students!


For information and suggestions about the colloquium please contact the colloquium coordinator:
Prof. Prashanth Jaikumar, Phone: 562-985-5592, Email:

Directions to Campus

  • Access to Campus
  • Campus Maps
  • Parking on campus: contact the coordinator of the colloquium. If not reachable, call the department office (562) 985-7925. If none of these are available at the time you need information, call (562) 985-4146 or go to the drive-through information booth at the main campus entrance (on Beach Drive, near the crossing to Bellflower).
  • Walk (or ask for a ride on an on-campus shuttle) to the department office: Hall of Sciences, Room 220 (HSCI-220). The coordinator will provide the necessary informations.
  • Any question or problem: call the colloquium coordinator or the department office (562) 985-7925.

Colloquia Sponsors:

We acknowledge with gratitude donations and support from the following present sponsors:

  • H.E. and H.B. Miller
  • Benjamin Carter
  • The American Physical Society
  • Anonymous

We also acknowledge with gratitude our past donors: The Forty-Niner Shops, Inc., The Northrop Grumman Foundation, Sandra Dana, Anonymous.

If you wish to support the Colloquium, please contact the colloquium coordinator or the department chair. Thank you!

Academic Year 2014-2015

Date Title Speaker and Affiliation
February 2,2015 Rapid Sequencing of Individual DNA Molecules with Graphene Nanogaps Henk Postma, CSUN
February 9, 2015 Probing and Controlling Ultrafast Electron Motion with Attosecond Transient Absorption Spectroscopy Michael Chini, UCF
February 11, 2015 Transparent Conducting Oxide Active Plasmonics and Metasurfaces: Ultrasmall and Ultrathin Optics Howard Lee, Caltech
February 16, 2015 Nuclear Magnetic Resonance in Condensed Matter Physics: Unconventional Superconductivity, Quantum Magnetism, and Other Magnificent Tales Georgios Koutroulakis, UCLA
February 18, 2015 Few-body Physics in Ultracold Atoms: Observation of Geometric Scaling Symmetry in Li-Cs-Cs Efimov States Shih-Kuang Tung, NU
February 23, 2015 Molding Light with Flat Optics Myoung Hwan Kim, Columbia U.
February 25, 2015 Quantum Phenomena and Layered Heterostructures Claudia Ojeda-Aristizabal, UCB
March 9, 2015 What is a Sagnac interferometer and what can it do? Jing Xia, UC Irvine.

Colloquia Schedule