# Presentation: 752394

## 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 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.

## 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

- 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.

## Raman Measurement

## 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.

## 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

## Slide 12

## Slide 13

## Results

## Further Results

## 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](http://en.wikipedia.org/)_
- “Detector”
- http://en.wikipedia.org