1. 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

2. Abstract The purpose of this experiment is to fabricate Cr 4+ ion doped laser crystals and 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.

3. Objectives 1.Material preparation To uncover a proper host for the Cr 4+ ion through the research of the LiInSiO 4 and CaSiO 4 systems. 1.Optical characterization of materials To compare a glass ceramic doped with nanocrystallite Cr 4+ ions and bulk laser crystals, such as Cr 4+ : Mg2SiO4 or Cr 4+ : Ca2GeO4 to observe whether it has the same characteristics as the individual bulk crystals.

4. 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

5. 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

6. Laser System Diode-pumped Nd:YAG laser: 532nm, 8ps, 82MHz, 1.85 W Dye Laser with mode-locking: 610nm, 1ps, 82MHz, 170mw Q-switch pulsed Nd:YAG laser: 532nm, ~5ns, 30Hz, ~330mJ Pulsed Dye Amplifier: 610nm, ~1ps, 30Hz, ~5mJ/pulse Synchronization Laser System: Thandar Myint

7. 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.

8. Raman Measurement

9. Spectrometer/ Detector 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 device which is designed to detect the presence of something as well as to emit a signal in response.

10. Experimental Set Up F. Colon

11. 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

14. Results

15. Further Results

16. 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.

17. 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.

18. 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

19. References “Characteristics of Laser Light” –http://en.wikipedia.org “What is a Laser?” –http://en.wikipedia.orghttp://en.wikipedia.org “Detector” –http://en.wikipedia.org