Dr. Kenneth G. Libbrecht
Professor of Physics


Current Research

The Physics of Crystal Growth and Pattern Formation in Ice.  
This project is essentially a case study of the growth of ice crystals from the vapor phase, the purpose of which is to better understanding molecular attachment physics and pattern formation in nonlinear nonequilibrim systems.  The diverse morphologies seen in snow crystals are largely due to the bizarre temperature dependence of ice crystal growth rates, a phenomenon that was discovered 75 years ago and remains unexplained to this day.  We have been making precise measurements of the growth rates of the different facets of ice crystals under controlled conditions to gain insights into the temperature dependent molecular structure of the ice surface and how it affects crystal growth. (1997-present, on and off)


Review Paper: Physical Dynamics of Ice Crystal Growth

Monograph (540 pages): arxiv.org/abs/1910.06389 (higher resolution, by chapter here)

Really, it's the perfect gift: Snowflake Books

Some Past Research

aboratory Instrumentation for Physics Education.  We developed numerous instruments that are being used in physics teaching labs at Caltech and at universities around the world, including an ion trapping apparatus, a picometer-resolution laser interferometer, a magneto-mechanical harmonic oscillator, and a tunable diode-laser apparatus. I started Newtonian Labs to sell these teaching tools. (2014-2018)

Electronics Consulting at hQphotonics (2016-2019)

Advanced detector development for the Laser Interferometer Gravitational-wave Observatory (LIGO).
  The LIGO project studies gravitational-wave signals from violent astrophysical events, such as supernovae or coalescing neutron stars and black holes.  For more information on all aspects of the LIGO project, see the LIGO web site.  My work in LIGO focused on: 1) an instrument called the Thermal Noise Interferometer (TNI), which was a test-bed suspended interferometer at Caltech, and 2) a photothermal interferometer for measuring the properties of optical coatings used in the LIGO detectors. (1999-2014)

Laser Cooling and Trapping of Neutral Atoms.  We built laser-cooled magneto-optical atom traps in the early 1990s that could capture and observe individual cesium atoms.  This technology was used to investigate the dynamics of atom trapping in the low-atom-number limit.  We also investigated the use of microfabricated planar current structures for making microscopic magnetic atom traps. (1993-2000)

Helieseismology and the Large-Scale Structure of the Sun.  
Convective motions near the solar surface generate acoustic waves that resonate inside the Sun, resulting in global oscillation modes with periods around five minutes.  We made extensive measurements of these global modes in the late 1980s at Big Bear Solar Observatory, recording Doppler images of the entire solar disk each minute for many months on end.  Analysis of these tens of thousands of images allowed us to measure the solar mode frequencies to unprecedented accuracy.  By examining the mode frequencies and amplitudes, as well as the frequency splittings of mode multiplets, information about the interior structure and dynamics of the Sun could be extracted, including a measure of the interior rotation rate of the Sun. (1984-1995)

Professional Info

Curriculum Vita

List of Publications

Contact Info
  •  E-mail: kgl@caltech.edu
  •  Phone: 626-395-3722
  •  Address: Physics Department, Caltech 264-33, Pasadena, CA 91125