Topic report C. C. Tsai Speaker: C. C. Tsai Adviser: Dr. S. L. Huang 2011/12/29 Specification of handheld probe for dermatology 2016/6/111

Outline Collimator design for single mode fiber Performances of scan lens and scan mirror Short pass coating for scan mirror Naked eye vision design for white light LED Specification of dermatologic handheld probe Discussion 2016/6/112

Collimator design for single mode fiber 2016/6/113 Fiber type: Thorlabs, #SMF-28-J9 for Cr 4+ :YAG (NA: 0.14) d NA: 0.14, θ: 16 ° θ SMF Collimator Note: Assume the diameter of achromatic lens (collimator) is 5 mm and its diameter of clear aperture is d = 4 mm, the focal length should be 1.42 mm. For Thorlabs’ product, focal length = 1.5 mm (#AC C) is the best choice for NA = 0.14 SMF.

2016/6/114 Performance of scan lens Gaussian profile F: focal length D: diameter of entrance pupil d: collimated beam size λ 0 : central wavelength Δ λ: 3-dB bandwidth

2016/6/115 Performance of scan lens Thorlabs, #LSM02

2016/6/116 Performance of scan mirror Galvo mirror (32 frame/sec) Y-axial golden coating with 6-mm area diamon-shaped mirror (small angle step rise time: 130 μm) Cambridge Technology, #8300K Galvo mirror + goniometric auto-stage (3-D scan) Mirror size : 12.7 mm 10mm

2016/6/117 Performance of scan mirror Galvo mirror (32 frame/sec) Tuning frequency: 53.8 kHz 1620 line/frame 3D-image acquisition time: 52.5 sec (HD-TV pixel number: 1080 × 1620)

2016/6/118 Short pass coating for scan mirror 45° incident, VIS pass & IR reflect Simulation of fused silica substrate with TiO 2 and SiO 2 stacks

2016/6/119 Naked eye vision design for white light LED LED emission area: 1.2 (mm) x 1.2 (mm), manufactured by Cree Co., USA LED emission power: 1W (200lm/W) Note: The white light LED source should be collimated as a near parallel light by means of parabolic reflector cup with 10 mm beam diameter.

2016/6/1110 White light Broadband beam-splitter Tube lens Scan mirror 5X eye piece 2-mm-thick axially- adjustable glass contact window Single mode fiber line Collimators Mirror White light source wire Function-switched line scan lens + - Emission area: 1 (mm) x 1 (mm) Focus area: 1W (200lm/W)

Specification of dermatologic hand held probe 2016/6/1111 Scan lens3X5X10X3X5X10X FOV14 × 149 × 95 × 528 × 2818 × 1810 × 10 Entrance pupil size 48 DOF R transversal R axial 3.7 Scan rate1620 line/s Frame rate32 frame/s Unit: mm

Discussion (1)Substrate and coating of scan mirror need to be well designed. (2)White light LED will produce heat when set on the handheld probe. (3)The axial resolution or the DOF can be improved when enlarging the entrance pupil size of the scan lens. In other words, the size of scan lens should be larger. (4)Handheld probe structure design for all the optical and electrical elements 2016/6/1112

Thank you 2016/6/1113