Wideband Electrically Pumped 1050-nm MEMS-Tunable VCSEL for Ophthalmic Imaging
D. D. John, C. Burgner, B. Potsaid, M. Robertson, B. Lee, W. J. Choi, A. Cable, J. Fujimoto, and V. Jayaraman
Journal of Lightwave Technology, Vol. 33, Is. 16, Feb. 2 2015
We present first retinal images acquired with the new electrically-pumped 1050nm MEMS-VCSEL light source (in contrast with our previous optically-pumped lasers). The 63.8nm wide tuning range is the widest 1050nm MEMS-VCSEL source to-date.
We present the first measurements of the coherence length of the laser, and estimate that when swept at 300kHz the coherence length was greater than 200 meters (in air).
Lastly, Thorlabs scientist Dr. Benjamin Potsaid and students in the research group of Prof. James G. Fujimoto at MIT acquired high-resolution angiographic images using the new source, with increased sensitivity aided by a prototype Praevium-designed wide-band optical amplifier.
In this paper, we present a 1050-nm electrically pumped microelectromechanically tunable vertical cavity surface-emitting laser (MEMS-VCSEL) with a record dynamic tuning bandwidth of 63.8 nm, suitable for swept-source optical coherence tomography (SS-OCT) imaging. These devices provide reduced cost and complexity relative to previously demonstrated optically pumped devices by obviating the need for a pump laser and associated hardware. We demonstrate ophthalmic SS-OCT imaging with the electrically-pumped MEMS-VCSEL at a 400 kHz axial scan rate for wide-field imaging of the in vivo human retina over a 12 mm × 12 mm field and for OCT angiography of the macula over 6 mm × 6 mm and 3 mm × 3 mm fields to show retinal vasculature and capillary structure near the fovea. These results demonstrate the feasibility of electrically pumped MEMS-VCSELs in ophthalmic instrumentation, the largest clinical application of OCT. In addition, we estimate that the 3 dB coherence length in air is 225 ± 51 m, far greater than required for ophthalmic SS-OCT and suggestive of other distance ranging applications.
Published online: Feb. 2nd 2015, in The Journal of Lightwave Technology special issue on Biomedical Applications
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