Rear Mirrors for CO2 Laser Systems

Rear mirrors, typically GaAs, Ge, or ZnSe, are partial reflectors with a very high reflection-to-transmission ratio (99.0% to 99.7%), and are key optical components in laser resonators or laser cavities. Rear mirrors, like output couplers, are a part of the lasing process. Thus, high reflectivity is desired. The rear mirrors slight transmission is used in conjunction with power meters to test for laser resonator output power.

When laser resonator designs require rear mirrors to be total reflectors, Si, Cu, or Mo substrates are used, the latter being typically uncoated.

 

Specifications
Standards
Dimensional Tolerances
Diameter
Thickness (plano)
Thickness (radiused)
+0.000”-0.005”
+0.005”-0.010”
+/-0.010”
Parallelism
Plano
Radiused, Diameter < 1”
Radiused, Diameter >= 1”
<= 3 arc minutes
<= 10 arc minutes
<= 5 arc minutes
Clear Aperture (polished)
90% of diameter
Surface Figure (power/irregularity) at 0.63µm
Plano
Radiused
1 fringe/0.5 fringe
(varies depending upon radius)
Surface-Dig
20-10
Side 1: Reflectivity Tolerance at 10.6µm
99%: +2%
99.5%: +.2/-0%
99.7%: +1-0.1%
Side 2: AR Coating Reflectivity at 10.6µm
<= 0.20%
Part #
Description
Diameter
(inches)
Diameter
(mm)
Edge
Thickness
(inches)
Edge
Thickness
(mm)
Reflectivity
Radius**
Side 1/Side 2
234709
Ge
1.0
25.4
0.236
5.99
99.5%
15MCC/PO
722287
Ge
1.1
27.94
0.220
5.59
99.5%
20MCC/PO
432529
Ge
1.181
29.99
0.236
5.99
99.6%
30MCC/PO
766409
Ge
2.0
50.8
0.375
9.53
99.5%
30MCC/PO
536364
GaAs
1.0
25.4
0.236
5.99
99.7%
30MCC/PO
230089
GaAs
1.1
37.94
0.120
3.05
99.7%
20MCC/PO
911209
ZnSe
1.5
38.1
0.236
5.99
99%
20MCC/PO
*M is meter, CC is concave, PO is plano
Contact a II-VI sales representative for exact specifications.
Part #
Description
Diameter
(inches)
Diameter
(mm)
Edge
Thickness
(inches)
Edge
Thickness
(mm)
Reflectivity
Radius**
Side 1/Side 2
234709
Ge
1.0
25.4
0.236
5.99
99.5%
15MCC/PO
722287
Ge
1.1
27.94
0.220
5.59
99.5%
20MCC/PO
432529
Ge
1.181
29.99
0.236
5.99
99.6%
30MCC/PO
766409
Ge
2.0
50.8
0.375
9.53
99.5%
30MCC/PO
536364
GaAs
1.0
25.4
0.236
5.99
99.7%
30MCC/PO
230089
GaAs
1.1
37.94
0.120
3.05
99.7%
20MCC/PO
911209
ZnSe
1.5
38.1
0.236
5.99
99%
20MCC/PO
*M is meter, CC is concave, PO is plano
Contact a II-VI sales representative for exact specifications.

Specifications
Standards
Dimensional Tolerances
Diameter
Thickness (plano)
Thickness (radiused)
+0.000”-0.005”
+0.005”-0.010”
+/-0.010”
Parallelism
Plano
Radiused, Diameter < 1”
Radiused, Diameter >= 1”
<= 3 arc minutes
<= 10 arc minutes
<= 5 arc minutes
Clear Aperture (polished)
90% of diameter
Surface Figure (power/irregularity) at 0.63µm
Plano
Radiused
1 fringe/0.5 fringe
(varies depending upon radius)
Surface-Dig
20-10
Side 1: Reflectivity Tolerance at 10.6µm
99%: +2%
99.5%: +.2/-0%
99.7%: +1-0.1%
Side 2: AR Coating Reflectivity at 10.6µm
<= 0.20%