6
4.
Overview
LCOS-SLM is a liquid-crystal on silicon (LCOS) spatial light modulator that can modulate only the phase of
incident light. The phase of the incident light can be controlled arbitrarily by generating and displaying an
image using a DVI output device (PC, etc.).
LCOS-SLM has the following features:.
○
High precision phase modulation characteristics
○
High diffraction efficiency
○
High light utilization efficiency
Fig. 1 shows the concept of the phase modulation characteristics of the LCOS-SLM. The gradation value
of the image displayed on the PC becomes the value input to the LCOS-SLM, and the phase modulation
amount changes according to the input gradation value. The LCOS-SLM's non-linear response and phase
modulation characteristics, which vary from device to device, are corrected by adjusting parameters at the
time of shipment. As shown in Fig. 1, the phase modulation characteristics differ depending on the
wavelength used.
Fig.1
Phase Modulation Characteristics (Typical example)
Multilevel phase gratings can be displayed on LCOS-SLM to diffract light at any position. Please refer to
the Product Flyer for the efficiency of light diffracted (diffraction efficiency) at an arbitrary position when a
multilevel phase grating is displayed on the LCOS-SLM. Diffraction efficiency depends on the type of
LCOS-SLM.
0
1
2
3
4
5
6
0
32
64
96
128
160
192
224
256
入力階調値
位
相
変
調
量
π
[r
ad
]
700nm
633nm
532nm
405nm
Input signal level
P
h
as
e
m
o
du
la
tio
n
[
π
ra
d
.]
