Elmas mikroyuvarın elastik ışık saçılması, fotoışıma ve Raman izge ölçümleri

Over the past decades, morphology dependent resonances, the optical resonances occurring by the interaction of light with microspheres of various materials, were vastly investigated. Spherical microcavities have diverse applications due to their high concentration of modes in small volumes at optical frequencies and high Q factors. The localization of the electromagnetic waves inside the microsphere is realized by total internal reflection. Microspheres provide the concave surface for light to circumnavigate around the microcavity, giving rise to whispering gallery modes. Because of its unique lattice structure, robust physical properties, as well as its distinctive optical properties, different forms of diamond were vastly investigated for various applications. As is well known, nitrogen vacancy (NV) centers inside the diamond lattice give rise to such applications by replacing two carbon atoms by one nitrogen atom and a vacancy, that yields a floating electron at the NV- center. In this thesis, Raman and photoluminescence spectroscopy is performed with various diamond samples including a diamond microsphere. The measurement setup is presented for both spectroscopies. NV centers exhibit 575 nm or 637 nm zero phonon lines along with their corresponding phonon side bands depending on the charge state of the point defect, NV0 and NV-, respectively. A 572 nm inelastic Raman scattering (1332.25 cm-1) is observed with 532 nm excitation laser due to the vibrational state of carbon-carbon bonds with sp3 configuration, whereas sp2 hybridization (1444.56 cm-1) yields inelastically scattered photons with 576 nm wavelength. It is possible to identify the main impurities within the diamond lattice, and confirm the carbon-carbon bonds with spectroscopic techniques. In addition, the demonstration of a diamond microsphere whispering gallery modes resonator in the standard telecom wavelengths between 1426.10 nm and 1427.42 nm in the 90° elastic light scattering for both transverse magnetic and transverse electric polarizations is realized. The highest measured whispering gallery mode Q-factor is on the order of 104, and the mode spacing 0.332 nm for both transverse polarizations. The coupling of the continuous wave tunable infrared excitation laser to the diamond microsphere is achieved by a single mode silica optical fiber half coupler. All in all, diamond is a unique material with particular optical properties. Utilizing such properties in a spherical morphology can give rise to distinctive applications. It is essential to observe the aspects of the whispering gallery modes created by the light circumnavigating a diamond microsphere such as mode spacing and Q-factor to classify the properties of a 1 mm synthetically grown spherical diamond microresonator. Such a diamond resonator can further be used as stable optical frequency comb generators or lasing microcavities by exploiting the nitrogen vacancy centers present within the lattice of the diamond.