lasers and electro-optics
Ying-Chih Chen
Professor of Physics
Hunter College of CUNY
Our research is focused on the physics, devices and materials of lasers.
Laser arrays
Combining the output power of a large number of
individual lasers in the form of laser array is a commonly used method of
generating high power. When a number of lasers are placed in close
proximity to one another, the interaction among the elements can lead to phase
locking. When the adjacent elements have the same phase, the interference
is constructive, resulting in enhanced power. One the other hand, if the
adjacent elements have a phase difference of 180 degrees, the interaction is
destructive, resulting in cancellation of power. In some cases, the
interaction among the elements can never be stabilized, resulting in
unstable or chaotic output power. The goal for this research is to study
the nature of the interaction among the elements in the laser array, the
condition for phase locking, and how to achieve stable phase locking.
Solid-state lasers and fiber
lasers
We are working on the physics and technology of
diode-pumped monolithic solid-state lasers. The general goal is to
develop miniature solid-state lasers using the simplest structure yet still
capable of delivering intense short pulses with superior beam quality and
spectral purity . The monolithic lasers typically consist of a single
crystal with the end surfaces polished and coated to form a laser cavity.
In these monolithic solid-state lasers, there is
no moving parts or discrete optical components. The functions of the
conventional laser cavity, including mode control, frequency control,
polarization control and frequency selection, are performed by a multifunction
laser material. An example of the multifunctional laser material is the
chromium and neodymium co-doped YAG ( Yttrium aluminum garnet ) crystal in
which the chromium ions serve as light modulator, polarizer and aperture and
the neodymium ions serve as the light emitter. Using chromium-neodymium
co-doped material to form a monolithic cavity, we have successfully developed a
series of monolithic high-power pulsed lasers that emit short pulses of
nanosecond to picosecond pulse duration in single frequency. The beam
quality is close to the theoretical limits. The pulse energy generated from the
monolithic lasers is one thousand times higher than that of the conventional
solid-state lasers.
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Last Updated on August 10, 1999.