Physics Research

Quantum and Nonlinear Optics

Quantum and nonlinear optics are two exciting areas of physics that explore fundamental questions about the universe while at the same time developing new technologies for our ever-changing world. Equipped with the latest in laser technology, the laboratory provides an environment where students can be introduced to hands-on research. With experiments ranging from the propagation of very intense laser pulses to quantum teleportation with single photons, the laboratory offers opportunities as broad as the imagination.

Sensors Using Quantum Cascade Lasers

Research by Dr. Gottipaty Rao focuses on methods of detecting very small amounts of various gasses. This has important uses in applications including monitoring pollutants, detecting explosives, studying combustion, and medical diagnostics. The research laboratory provides a wealth of opportunities for undergraduate students.

Highly Sensitive Resonant Photo-acoustic Spectrometer for Trace Gas Detection

Recent advances in the detection of trace gases with very high sensitivity, selectivity and in real time have opened a variety of new applications. Photoacoustic spectroscopy offers high sensitivity, compact size, ruggedness, simple optical alignment, low cost, and can be employed in an industrial environment. We are developing a highly sensitive photacoustic spectrometer with a multi-pass cell for the detection of nitrogen dioxide at parts per billion level based on quantum cascade lasers. The technique has extensive applications in environmental science and the power industry.

Development of Cavity Ring-Down Spectrometer (CRDS)

We are developing a high sensitivity cavity ring-down spectrometer to measure the rate of absorption of a light pulse confined in a stable optical cavity with a high Q-factor formed by two highly reflective mirrors (reflectivity R > 99.99%). A short laser pulse coupled into the cavity is reflected back and forth and, every time the light is reflected, a small fraction (1-R) leaks out. This leads to an exponential decay of the pulse in the cavity. The light is detected by a photomultiplier and the data recorded. The ring-down time of the cavity is measuorange from the exponential decay of the intensity of light leaking out of the cavity. We will use the spectrometer for trace gas detection of species such as nitrogen dioxide and nitric oxide at the sub-parts per billion level.

Trace Gas Detection Employing Quantum and Interband Cascade Lasers Employing Amplitude and Frequency Modulation Techniques

The recent developments in the availability of mid-infraorange quantum cascade lasers have opened exciting possibilities to detect and estimate trace gases in real time at sub-parts-per billion levels and in favorable cases at sub-parts-per trillion levels. We are developing an extremely sensitive sensor for nitrogen oxides based on amplitude and frequency modulation techniques coupled to a multi-pass Herriott cell. The sensors have applications in medical diagnostics, environmental monitoring, combustion studies, and a variety of industrial applications.

High-Resolution Laser Spectroscopy

Dr. Gottipaty Rao and Dr. Eugene Hecht have led students in research using lasers to probe the hyperfine structure of atoms.

Atomic Hyperfine Structure Studies Employing High-Resolution Laser

The hyperfine structure of atomic levels can be described in terms of the interaction of atomic electrons with the nuclear multipole moments—nuclear charge, magnetic dipole, electric quadrupole, magnetic octupole, and higher order terms. Doppler free techniques such as saturation spectroscopy and its variants, intermodulated optogalvanic spectroscopy (IMOGS) and polarization intermodulated excitation (POLINEX) and Doppler limited spectroscopy techniques are employed for the measurement of the hyperfine structure of atomic states.

Holography

Adelphi’s state-of-the-art laser optics lab allows undergraduate students the opportunity to become familiar with current optics technology and its applications. Dr. Gottipaty Rao oversees holography research.

One such application is in using bacteriorhodopsin as a recording material for dynamic holographic applications.

For approximately ten years, we have been preparing excellent quality optical holograms using films and plates. Now we are investigating the possible utilization of bacteriorhodopsin (BR) as a recyclable, real-time holographic recording material. BR offers excellent high resolution for holographic recording (better than 5000 lines/mm) which is comparable to or better than the best available emulsions, a wide range of spectral sensitivity (400-600 nm) covering most of the visible part of the electromagnetic spectrum, write and erase timescales in the microsecond range, and millions of write/read operations. This material needs no further processing or wet chemical development procedures after exposure. One additional feature of the BR films is that polarization recording is possible. When fully developed, this technique has applications in optical holography, industry, and defense.

Energy and Intelligence Flame Analysis System (IFAS)

Energy

Adelphi’s Department of Physics includes many undergraduate opportunities for energy research. Notable past research has been done with flame analysis and diagnostics, coal-oil mixtures (“coal slurries”) as sources of energy, etc.

Paper: Physio-Chemical Modeling of Coal and Coal/Biomass Slurries for Gasification and Direct Combustion Applications (PDF)

IFAS

IFAS, or the Intelligent Flame Analysis System, is a flame analysis and diagnostic tool developed at Adelphi. The system uses a unique combination of spectral imaging techniques and special computer software to determine combustion gas distributions in furnace flames. Under the direction of Dr. John P. Dooher, undergraduate students have the opportunity to work with the IFAS for a variety of applications.

Paper: IFAS Presentation (PDF)