Salman Rushdie’s Picture of Coexistence: Faith and Doubt in “The Parting of the Arabian Sea”

Graduate Textual or Investigativ

Dark state lasers

We propose a new type of laser resonator based on imaginary "energy-level splitting" (imaginary coupling, or quality factor Q splitting) in a pair of coupled microcavities. A particularly advantageous arrangement involves two microring cavities with different free-spectral ranges (FSRs) in a configuration wherein they are coupled by "far-field" interference in a shared radiation channel. A novel Vernier-like effect for laser resonators is designed where only one longitudinal resonant mode has a lower loss than the small signal gain and can achieve lasing while all other modes are suppressed. This configuration enables ultra-widely tunable single-frequency lasers based on either homogeneously or inhomogeneously broadened gain media. The concept is an alternative to the common external cavity configurations for achieving tunable single-mode operation in a laser. The proposed laser concept builds on a high-Q "dark state" that is established by radiative interference coupling and bears a direct analogy to parity-time (PT) symmetric Hamiltonians in optical systems. Variants of this concept should be extendable to parametric-gain based oscillators, enabling use of ultrabroadband parametric gain for widely tunable single-frequency light sources

Integrated optical isolators using electrically driven acoustic waves

We propose and investigate the performance of integrated photonic isolators based on non-reciprocal mode conversion facilitated by unidirectional, traveling acoustic waves. A triply-guided waveguide system on-chip, comprising two optical modes and an electrically-driven acoustic mode, facilitates the non-reciprocal mode conversion and is combined with modal filters to create the isolator. The co-guided and co-traveling arrangement enables isolation with no additional optical loss, without magnetic-optic materials, and low power consumption. The approach is theoretically evaluated and simulations predict over 20 dB of isolation and 2.6 dB of insertion loss with 370 GHz optical bandwidth and a 1 cm device length. The isolator utilizes only 1 mW of electrical drive power, an improvement of 1-3 orders of magnitude over the state-of-the-art. The electronic driving and lack of magneto-optic materials suggest the potential for straightforward integration with the drive circuitry, possibly in monolithic CMOS technology, enabling a fully contained `black box' optical isolator with two optical ports and DC electrical power.Comment: 14 pages, 5 figures, 1 table. Relies on an acoustic-optical multiplexer introduced in arXiv:2007.11520, which has been separated out in this updated version of the paper for clarity. Additionally, this updated version included additional discussion of design considerations of the isolato

Tunable coupled-mode dispersion compensation and its application to on-chip resonant four-wave mixing

We propose and demonstrate localized mode coupling as a viable dispersion engineering technique for phase-matched resonant four-wave mixing (FWM). We demonstrate a dual-cavity resonant structure that employs coupling-induced frequency splitting at one of three resonances to compensate for cavity dispersion, enabling phase-matching. Coupling strength is controlled by thermal tuning of one cavity enabling active control of the resonant frequency-matching. In a fabricated silicon microresonator, we show an 8 dB enhancement of seeded FWM efficiency over the non-compensated state. The measured four-wave mixing has a peak wavelength conversion efficiency of -37.9 dB across a free spectral range (FSR) of 3.334 THz ($\sim$27 nm). Enabled by strong counteraction of dispersion, this FSR is, to our knowledge, the largest in silicon to demonstrate FWM to date. This form of mode-coupling-based, active dispersion compensation can be beneficial for many FWM-based devices including wavelength converters, parametric amplifiers, and widely detuned correlated photon-pair sources. Apart from compensating intrinsic dispersion, the proposed mechanism can alternatively be utilized in an otherwise dispersionless resonator to counteract the detuning effect of self- and cross-phase modulation on the pump resonance during FWM, thereby addressing a fundamental issue in the performance of light sources such as broadband optical frequency combs

The effects of drug and fatty acid binding on human serum albumin fluorescence

In order to create a laboratory experiment focused on Fluorescence Resonance Energy Transfer for undergraduate biochemistry students at Ball State University, Human Serum Albumin, an abundant and sponge-like blood protein, was studied through the eyes of a spectrofluorometer. HSA binds very readily to many types of ligands, including drugs and fatty acids. When the lone tryptophan molecule within HSA gets excited, it fluoresces. Changing the shape of the HSA molecule by adding a fatty acid, like palmitic acid, changes the type and intensity of the fluorescence given off by the tryptophan. Adding a drug that can participate in Fluorescence Resonance Energy Transfer, like tetracycline, before adding a fatty acid allows one to quantitatively study the change in shape of the HSA molecule by calculating the exact distance between the tryptophan and the tetracycline. Overall, this research project showed promising results for this idea, but time constraints and difficulties in producing consistent data in the later stages of the project detracted from the ability to form a final unifying conclusive product.Honors CollegeThesis (B.?

Adult sex offenders in youth-oriented institutions: evidence on sexual victimisation experiences of offenders and their offending patterns

This study investigates child sexual abuse committed by adult males in youth-oriented institutions. Foreword There is significant interest in the issue of child sexual abuse committed in institutional settings. This study uses information collected from a sample of 23 convicted Canadian sex offenders to examine key elements of the offending. Issues explored include the nature of the offender’s involvement with institutions, their own prior sexual victimisation experiences, factors influencing the selection of victims and the locations where the sexual assaults occurred. Particularly telling was the length of time offenders spent at an institution prior to initiating the assaults and the potential to avert offending by reducing opportunities to offend, as well as the associated danger evident in allowing staff—without supervision—to transport children outside of an institutional setting, given the frequency of the assaults that occurred offsite