LCOS-SLM characteristics

Light resistance

When an LCOS-SLM is irradiated with a high-power laser, physical damage or irreversible characteristic changes may occur. To see if such damage or irreversible characteristic changes will occur, laser irradiation tests are performed and the test results are then examined. Physical damage includes damage to the transparent electrode, dielectric multilayer film and aluminum mirror, and also thermal damage caused by boiling of the liquid crystal materials. Irreversible characteristic changes may occur in the materials making up of the LCOS-SLM due to two-photon absorption when irradiated by an ultra-short pulsed laser or due to irradiation with an ultraviolet laser (400 nm or shorter wavelengths). Also, reversible changes in characteristics may result from the liquid crystal temperature characteristics accompanying a temperature rise caused by the light absorption in the LCOS-SLM. After the irradiation tests, the outer appearance of the damage is checked and the output image and phase modulation are evaluated. If an abnormal condition is found when no voltage is applied to the LCOS-SLM, it is determined as physical damage. If an abnormal condition is found when voltage is applied, it is determined as an irreversible characteristic change.

The tables below show data examples obtained after the light resistance test. The light resistance depends on the averaged power of light (entire incident light) entering the LCOS-SLM and the peak power (light power density) incident per unit area. If the X15213-05 LCOS-SLM is used in the UV region at 400 nm or shorter wavelengths, it may sustain damage. Please consult us when using it with UV light at 400 nm or shorter wavelengths.

X15213-02

Light source

Beam diameter
(mm)
[at 1/e2]

Irradiation
time

Irradiation light intensity

Peak power

Results

Type

Wavelength
(nm)

Pulse
width

Repetition
rate
(kHz)

Average
output
(W)

Output power
per unit area
(W/cm2)

Peak 
output
power

Output 
power per
unit area

Damage


Characteristic change

Ti:S laser
(pulse)

800

50 fs

1

φ9

3  hours

2.7

4.3

108 GW

170 GW/cm2

None

Seen

Ti:S laser
(pulse)

800

50 fs

1

φ11

10  hours

2.7

2.9

108 GW

114 GW/cm2

None

None

Ti:S laser
(pulse)

800

30 fs

0.01

φ18

6  hours

0.05

0.02

333 GW

131 GW/cm2

None

None

X15213-03B

Light source

Beam diameter
(mm)
[at 1/e2]

Irradiation
time

Irradiation light intensity

Peak power

Results

Type

Wavelength
(nm)

Pulse
width

Repetition
rate
(kHz)

Average
output
(W)

Output power
per unit area
(W/cm2)

Peak 
output
power

Output 
power per
unit area

Damage

Characteristic change

YAG laser
(CW)

1064

-

-

φ2.5

1 hour

2.0

40.7

-

-

None

None

YAG laser
(CW)

1064

200 ns

80

φ2.5

1 hour

2.0

40.7

0.25 KW

5.1 KW/cm2

None

None

Pulsed
laser

1030

670 fs

1

φ4.5

10 hours

0.6

3.8

1.8 GW

11.3 GW/cm2

None

None

Pulsed
laser

1030

1.37 ps

30

φ8.11

8 hours

5.2

10.1

0.25 GW

0.49 GW/cm2

None

None

Pulsed
laser

1030

11.4 ns

10

φ13

8 hours

17.4

13.1

0.31 GW

0.23 MW/cm2

None

None

X15213-03CL/-03CR

Light source

Beam diameter
(mm)
[at 1/e2]

Irradiation
time

Irradiation light intensity

Peak power

Results

Type

Wavelength
(nm)

Pulse
width

Repetition
rate
(kHz)

Average
output
(W)

Output power
per unit area
(W/cm2)

Peak 
output
power

Output 
power per
unit area

Damage

Characteristic change

Fiber
laser
(CW)

1070

-

-

φ5.5

10 hours

743

3127

-

-

None

None*1

*1 Depends on water-cooling conditions. Please contact us for details.

X15213-13

Light source

Beam diameter
(mm)
[at 1/e2]

Irradiation
time

Irradiation light intensity

Peak power

Results

Type

Wavelength
(nm)

Pulse
width

Repetition
rate
(kHz)

Average
output
(W)

Output power
per unit area
(W/cm2)

Peak 
output
power

Output 
power per
unit area

Damage

Characteristic change

CW
laser

532

-

-

φ8.45

8 hours

10

17.8

-

-

None

None

X15213-16

Light source

Beam diameter
(mm)
[at 1/e2]

Irradiation
time

Irradiation light intensity

Peak power

Results

Type

Wavelength
(nm)

Pulse
width

Repetition
rate
(kHz)

Average
output
(W)

Output power
per unit area
(W/cm2)

Peak 
output
power

Output 
power per
unit area

Damage

Characteristic change

Pulsed
laser

515

4 ps

25

φ3.7

27 hours

0.162

1.5

1.6 MW

30 MW/cm2

None

None

60 hours

0.36

3.3

3.6 MW

67 MW/cm2

Seen

Seen

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