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Synthesis & Study of Fluorescence Synthesis & Study of Fluorescence Properties of Cr-doped LiInSiO Properties of Cr-doped LiInSiO 4 4 - - Ca Ca 2 2 SiO SiO 4 4 Solid State Solutions Solid State Solutions By: Caesar Pereira (Archbishop By: Caesar Pereira (Archbishop Stepinac H.S.) Stepinac H.S.) Supervising Scientist: Prof. V. Supervising Scientist: Prof. V. Petricevic (CCNY) Petricevic (CCNY) Senior Scientist: Dr. A. Bykov Senior Scientist: Dr. A. Bykov (CCNY) (CCNY)

Synthesis & Study of Fluorescence Properties of Cr-doped LiInSiO 4 - Ca 2 SiO 4 Solid State Solutions By: Caesar Pereira (Archbishop Stepinac H.S.) Supervising

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Synthesis & Study of Fluorescence Synthesis & Study of Fluorescence Properties of Cr-doped LiInSiOProperties of Cr-doped LiInSiO44--

CaCa22SiOSiO44 Solid State Solutions Solid State SolutionsBy: Caesar Pereira (Archbishop Stepinac H.S.)By: Caesar Pereira (Archbishop Stepinac H.S.)

Supervising Scientist: Prof. V. Petricevic (CCNY)Supervising Scientist: Prof. V. Petricevic (CCNY)Senior Scientist: Dr. A. Bykov (CCNY)Senior Scientist: Dr. A. Bykov (CCNY)

BackgroundBackground

The goal of my research is to develop the The goal of my research is to develop the most effective crystallites for near-infrared most effective crystallites for near-infrared optical amplifiers using the Croptical amplifiers using the Cr4+4+ ion ion

This research will aid in the development This research will aid in the development of new and more effective lasing media.of new and more effective lasing media.

The results will bring a deeper The results will bring a deeper understanding of the different olivine understanding of the different olivine structures’ optical properties, such as structures’ optical properties, such as fluorescence.fluorescence.

What are What are LASERLASERs?s? ““LASERLASER” is an acronym for ” is an acronym for LLight ight AAmplification by mplification by

SStimulated timulated EEmission of mission of RRadiationadiation When a laser ion is pumped with energy, its electrons When a laser ion is pumped with energy, its electrons

move to a higher energy levelmove to a higher energy level The electrons after being excited will spontaneously fall The electrons after being excited will spontaneously fall

back to the ground stateback to the ground state At this moment “spontaneous light emission” occurs. At this moment “spontaneous light emission” occurs.

This is called fluorescence.This is called fluorescence.

Laser PropertiesLaser Properties

MonochromaticMonochromatic It contains one specific wavelength of light It contains one specific wavelength of light

(one color)(one color)CoherentCoherent

Each photon moves in phase Each photon moves in phase with each other (organized)with each other (organized)

DirectionalDirectionalA laser light has a highly focused tight beam A laser light has a highly focused tight beam

and is very strong and concentratedand is very strong and concentrated

Solid-State LasersSolid-State Lasers Although the amplifying media Although the amplifying media

can be solid, liquid, or gas, we can be solid, liquid, or gas, we chose to use solid-state media for chose to use solid-state media for our research, such as crystals our research, such as crystals

In my project, the amplifying In my project, the amplifying medium is a crystal containing medium is a crystal containing CrCr4+4+ ions as dopands. ions as dopands.

The reason crystals are different The reason crystals are different colors is because the electron colors is because the electron configuration of the ion configuration of the ion determines what color we determines what color we perceive.perceive.

In our samples the electron In our samples the electron configuration of the Cr4+ ion configuration of the Cr4+ ion appears to be the color green.appears to be the color green.

HistoryHistory

Previous research in this project revealed Previous research in this project revealed the optimal amount of CrOthe optimal amount of CrO22 to be used in to be used in an olivine crystallite structure is between an olivine crystallite structure is between 0.5% and 0.1% of the total weight.0.5% and 0.1% of the total weight.

The CrThe Cr4+4+ ion is the desired valence state ion is the desired valence state for Cr because its fluorescence is greater for Cr because its fluorescence is greater than the Crthan the Cr3+3+ ion and also it encompasses ion and also it encompasses a larger range of wavelengths in the near-a larger range of wavelengths in the near-infrared region we are investigating.infrared region we are investigating.

AbstractAbstract

The goal of my project, now, is to find the best The goal of my project, now, is to find the best suitable host for the Crsuitable host for the Cr4+4+ ion by combining the ion by combining the elements calcium, lithium, indium, silicon, and elements calcium, lithium, indium, silicon, and oxygen to achieve the optimal “Host” crystal oxygen to achieve the optimal “Host” crystal structure, in particular of Listructure, in particular of LixxInInxxCaCayySiOSiO44. These . These compounds will be combined in different compounds will be combined in different concentrations to find which mixture gives the concentrations to find which mixture gives the desired fluorescence. The crystals obtained from desired fluorescence. The crystals obtained from this research will be effective amplifying media this research will be effective amplifying media for use in optical fiber communications, remote for use in optical fiber communications, remote sensing and other photonics applications.sensing and other photonics applications.

MaterialsMaterials The following compounds The following compounds

are being studied as host are being studied as host materials: materials: indium oxide (Inindium oxide (In22OO33), ), lithium carbonate (Lilithium carbonate (Li22COCO33), ), silicon oxide (SiOsilicon oxide (SiO33), and ), and calcium oxide (CaOcalcium oxide (CaO22) with ) with chromium oxide (Crchromium oxide (Cr22OO33) as ) as the dopand the dopand

Temperature-Controlled Temperature-Controlled Furnace Furnace

Electronic ScaleElectronic Scale MortarsMortars CruciblesCrucibles Round paperRound paper Fluorescence setupFluorescence setup

MethodsMethods

Before preparing the powders, stoichiometry Before preparing the powders, stoichiometry was used to calculate the weights of each of was used to calculate the weights of each of the compoundsthe compounds

After weighing out each compound carefully After weighing out each compound carefully on a very precise scale, the compounds were on a very precise scale, the compounds were mixed in a mortarmixed in a mortarEthanol was added to each powder to make it Ethanol was added to each powder to make it

homogeneous (uniform) but later on evaporated homogeneous (uniform) but later on evaporated out under a fume hood so as not to change the out under a fume hood so as not to change the properties of our compoundsproperties of our compounds

Methods (continued)Methods (continued)

The compounds underwent long periods of The compounds underwent long periods of heating in the furnace ~24 hours.heating in the furnace ~24 hours.Each powder was heated at 1100°C to obtain the Each powder was heated at 1100°C to obtain the

CrCr4+4+ ions needed for our crystal synthesis ions needed for our crystal synthesis Eight different mixtures were madeEight different mixtures were made

The difference between each mixture was how The difference between each mixture was how much lithium, indium, and calcium each one much lithium, indium, and calcium each one containedcontained

Compounds UsedCompounds Used

Place chart herePlace chart here

Characterization of FluorescenceCharacterization of Fluorescence

CrCr4+4+ Sample Fluorescence Sample Fluorescence Readings after 1100ºC Readings after 1100ºC

Under ConstructionUnder Construction

ResultsResults

Further analysis requiredFurther analysis required

AcknowledgementsAcknowledgements

Mentors: Dr. Bykov & Prof. PetricevicMentors: Dr. Bykov & Prof. PetricevicNASA SHARP / NYCRINASA SHARP / NYCRINASA COSI & DoD NPC Summer NASA COSI & DoD NPC Summer

ProgramProgramCity College of New YorkCity College of New YorkCREST-CMMSCREST-CMMSNYC-MTANYC-MTA

ReferencesReferences "The Causes of Color," K. Nassau, Scientific "The Causes of Color," K. Nassau, Scientific

American, Volume 243, Number 4, American, Volume 243, Number 4, October1980, pp. 124-154. October1980, pp. 124-154.

““Introduction in optical properties measurements Introduction in optical properties measurements of laser crystals” & “Introduction in absorption of laser crystals” & “Introduction in absorption measurements,” A. Bykov.measurements,” A. Bykov.

Illustrations: http://www.howstuffworks.comIllustrations: http://www.howstuffworks.com Source #4Source #4 Source #5Source #5 Source #6Source #6 Source #7Source #7

The EndThe End