We demonstrate the application of an extended field of view microscope, combining photoacoustic and fluorescence label-free contrast modalities, for the ex vivo investigation of ocular tissues including the ciliary muscle in healthy rabbit eyes and surgical biopsies of benign nevi removed from human eyes. In the case of ciliary muscle samples, the intrinsic photoacoustic and the glutaraldehyde-induced autofluorescence signals were observed to be spatially complementary, offering specific and high resolution morphological information as regards to Pars plana and Pars plicata ciliary body portions, iris, and zonule fiber strands. On the other hand, the biopsy samples presented a remarkable spatial overlap of the two signals in the nevus region, indicating a positive correlation between them. The bimodal microscopy approach presented in this work, has the potential to contribute in the understanding of the physiological function of the eye involving the detailed study of the ocular accommodation system and the elucidation of ageing effects such as presbyopia. Finally, the proposed hybrid diagnostic approach could be employed for the differentiation between benign and malignant intraocular tumors of the uvea in surgical biopsies, simplifying the relevant procedures for this purpose.
We present the theoretical analysis of a novel optical beam steering technique (OBST) for fiber to free-space to fiber coupling schemes on optical breadboards. This technique uses glass wedges and plates to correct misalignments in the position and angle of beams on the breadboard. It can be used in any application where stable and robust coupling of light from an input to an output fiber is required, such as laser distribution boards for cold atom experiments in space. We examine the optical performance in terms of coupling efficiency (CE) for a number of different OBST systems and compare the results. Coupling efficiencies above 95% and positional and angular resolution of smaller than 5 μm and 5 μrad can be achieved using this technology.
We present a novel optical beam steering technique (OBST) for fiber to free-space to fiber coupling schemes on optical breadboards, which uses glass wedge pairs and plates to correct for angular and translational misalignments respectively. This technique finds application in proposed missions for atom quantum experiments in space, e.g. where laser beams are used to cool and manipulate atomic clouds. The key advantage compared to the conventional beam steering is that OBST permits extremely fine adjustments whilst being far less sensitive to alignment errors and mechanical drifts. Beam steering resolutions of better than 5 μrad and 2 μm are achieved, resulting in a resolution in coupling efficiency (CE) of 0.1%. The inclusion of OBST on an optical breadboard reduces the requirements on the pointing and position precision adjustment of the fiber couplers, leading to a much-simplified design. The simpler construction of the couplers combined with the reduced sensitivity to drifts increases the stability-reliability of the breadboard and reduces the production duration and cost. We demonstrate CE of up to 90%, with a stability of 0.2% in a stable temperature environment and 2% over a temperature range from 10-40 degrees Celsius. We do not observe any change in the performance after large temperature changes.