MULTI-SPOT LASER PROBE WITH MICRO-STRUCTURED DISTAL SURFACE
An optical surgical probe, configured to optically couple to a light source; comprising a cannula; a light guide within the cannula, configured to receive a light beam from the light source, to guide the light beam to a distal end of the light guide, and to emit the light beam at the distal end of the light guide; and a multi-spot generator at a distal end of the cannula, the multi-spot generator having a faceted proximal surface with oblique facets, configured to receive the light beam emitted at the distal end of the light guide and to split the received light beam into multiple beam-components, and a distal surface through which the multiple beam-components exit the multi-spot generator, wherein the distal surface is micro-structured with a modulation length smaller than a wavelength of the light beam in order to reduce the reflectance of light back into the probe.
1 . An optical surgical probe comprising:
a cylindrical cannula;
a light guide within the cannula, configured to receive a light beam from the light source, to guide the light beam to a distal end of the light guide, and to emit the light beam at the distal end of the light guide; and
a multi-spot generator at a distal end of the cannula, the multi-spot generator having
a faceted proximal surface with oblique facets, configured to receive the light beam emitted at the distal end of the light guide and to split the received light beam into multiple beam-components, and
a distal surface through which the multiple beam-components exit the multi-spot generator, wherein
the distal surface of the multi-spot generator is micro-structured with a modulation length smaller than a wavelength of the light beam.
2 . The probe of claim 1 , the distal surface of the multi-spot generator comprising:
micro-structures, with an average separation less than the wavelength of the light beam.
3 . The probe of claim 2 , the micro-structures comprising at least one of bumps, cones, prisms, pyramids, grooves, troughs, divots and a relief pattern.
4 . The probe according to claim 1 , wherein:
the distal surface of the multi-spot generator has a moth's eye structure.
5 . The probe according to claim 1 , wherein:
the distal surface of the multi-spot generator is micro-structured to have an effective index of refraction that reduces a reflection of the multiple beam-components by the distal surface of the multi-spot generator to below 1%.
6 . The probe of claim 1 , the multi-spot generator comprising:
a cured adhesive medium at a distal end of the cannula, the micro-structured distal surface being formed at a distal surface of the adhesive medium; and
a ball lens, disposed in the cured adhesive medium.
7 . The probe of claim 6 , the ball lens comprising:
a sapphire ball lens.
8 . A method for manufacturing a multi-spot generator for an optical surgical probe, the method comprising:
depositing an optically transmissive adhesive medium on the surface of the substrate with an applicator;
inserting an optical element into the adhesive medium;
placing a pin with an obliquely faceted distal end onto the adhesive medium to form an obliquely faceted proximal surface on the adhesive medium, thus forming a pin-adhesive-optical element-substrate assembly;
placing a cannula onto the pin-adhesive-optical element-substrate assembly to house the multi-spot generator within the cannula;
curing the adhesive medium to form a micro-structured distal surface on the adhesive medium; and
separating the substrate and the pin from the multi-spot generator housed within the cannula.
9 . The method of claim 8 , comprising:
micro-structuring the surface of the substrate with electron beam etching.
10 . The method of claim 8 , comprising:
micro-structuring the surface of the substrate by indenting the surface of the substrate with a micro-structured master-tool.
11 . The method of claim 10 , wherein:
the master-tool comprises a material harder than a material of the substrate; and
the master-tool is micro-structured with electron beam etching.
12 . The method of claim 8 , comprising:
micro-structuring the surface of the substrate by injection molding with a micro-structured mold-tool.
13 . The method of claim 8 , comprising:
depositing a mold release layer on the micro-structured surface of the substrate before the depositing of the adhesive medium.
14 . The method of claim 8 , wherein:
the micro-structured distal surface has a modulation length shorter than the wavelength of an operating light beam of the optical surgical probe.
15 . The method of claim 14 , wherein:
the micro-structured distal surface comprise at least one of
bumps, cones, prisms, pyramids, grooves, troughs, divots, a relief pattern, and a moth's eye structure.
16 . The method of claim 8 , the forming comprising:
forming the micro-structured distal surface with a micro-structure to have an effective index of refraction that reduces a reflection of the light beam by the distal surface to below 1%.
17 . The method of claim 8 , wherein:
the placing the cannula is performed before the placing the pin.
18 . The method of claim 8 , wherein:
a positioning of the optical element on the substrate precedes the depositing the adhesive medium on the surface.