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Nanoscale Cr 4+ – Doped Olivine Crystallites in Glass-Ceramics for NIR Optical Amplifiers and Lasers. By: Fayette Colon Mentor: Mikhail Sharonov Assistant Mentor: Thandar Myint. Abstract. The purpose of this experiment is to fabricate
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Nanoscale Cr 4+ – Doped Olivine Crystallites in Glass-Ceramics for NIR Optical Amplifiers and Lasers By: Fayette Colon Mentor: Mikhail Sharonov Assistant Mentor: Thandar Myint
Abstract • The purpose of this experiment is to fabricate Cr 4+ ion doped laser crystalsand characterize glass ceramics containing nanoscale crystallites of Cr 4 + - doped laser materials such as Cr 4+ : Mg2SiO4 and Cr 4+ : Ca2GeO4. The glass ceramic is important because it can be used in several applications such as the fiber amplifier, fiber laser and for other medical purposes.
Objectives • Material preparation • To uncover a proper host for the Cr 4+ ion through the research of the LiInSiO4 and CaSiO4 systems. • Optical characterization of materials • To compare a glass ceramic doped with nanocrystallite Cr4+ ions and bulk laser crystals, such as Cr 4+ : Mg2SiO4 or Cr4+ : Ca2GeO4 to observe whether it has the same characteristics as the individual bulk crystals.
What is a laser? • It is an acronym for Light Amplification by the Stimulated Emission of Radiation • A laser produces near- monochromatic light • Has a single precise wavelength or hue • The light is coherent • The photons emitted have a definite phase relationship • Laser beams are collimated • They are narrow and concentrated
Electronics to Support Synchronization Between the Lasers The circuit used two non-inverting operational amplifiers In a non-inverting input the output polarity is the same as the input polarity
Laser System: Diode-pumped Nd:YAG laser: 532nm, 8ps, 82MHz, 1.85 W Dye Laser with mode-locking: 610nm, 1ps, 82MHz, 170mw Synchronization Q-switch pulsed Nd:YAG laser: 532nm, ~5ns, 30Hz, ~330mJ Pulsed Dye Amplifier: 610nm, ~1ps, 30Hz, ~5mJ/pulse Laser System Thandar Myint
Importance of the Circuit • The circuit serves as a component to the laser system • It is designed to aid in synchronizing the pump and the signal pulses in order to reach the laser amplifier at the same time.
A Spectrometer is an optical instrument which measures the properties of light over a portion of the electromagnetic spectrum. The measured variable is often the intensity and the independent variable is the wavelength. A Detector is a devicewhich is designed to detect the presence of something as well as to emit a signal in response. Spectrometer/ Detector
Experimental Set Up F. Colon
Experimental Information • A HeNe laser was used; it generates a 632.3nm laser line and its power is about 1mW. • The light passed through a filter (which selectively transmits certain portion of light) then reflected onto a mirror at 45 degrees • The light beam then reflected onto a second mirror and through a second filter • The laser was again reflected onto a mirror through a lens (which is 12cm from the crystal) to be reflected on a fourth mirror and into the glass ceramic crystal • The light then scattered and was collected by a Camera Lens following which it went into the Spectrometer. • The Camera Lens must be finely adjusted to receive good focusing
Analysis of the Results • The graph shows the light intensity versus wavelength of HeNe laser. • The maximum power of the HeNe laser is located at 632.8nm. • The shape of the image is well-known Gaussian shape, which means that the intensity is concentrated in the center and gradually decreases at the tails. • Although this was merely a test trial for the experiment its importance lies with the layout of the experimental instruments.
Further Work • The Research team will use the results of the test trial to create a more efficient layout for the experiment. • Following which the high intensity laser will be used for the actual experiment along with the circuit created • Completion of this experiment is important because the data received will show the characteristics of the glass ceramic; obtaining this knowledge will lead to realize the proposed application such as optical amplifiers.
Acknowledgements • Mentors: Mikhail Sharnovo and Thandar Myint • NASA SHARP • NASA COSI and DoD NPC Summer Program • City College of New York • CREST –CMMS • NYC-MTA
References • “Characteristics of Laser Light” • http://en.wikipedia.org • “What is a Laser?” • http://en.wikipedia.org • “Detector” • http://en.wikipedia.org