At the end of November 2023, Hamamatsu launched the industry's first Sapphire SLM, which raises the average power threshold for LCOS to more than 700 W and has a measured power density of more than 3,127 W cm2. Next, in the form of a text version, I will quickly take you through the advantages of the most **LCOS.
Laser power density
There are three main types of irreversible damage to LCOS caused by bright light:
1. The laser energy is absorbed by LCOS, and the temperature continues to rise, resulting in phase drift. This damage threshold is determined by the average power of the laser and can be increased by refrigeration
2. For pulsed lasers, due to the extremely high instantaneous energy of a single pulse, it may also cause another kind of damage to LCOS. That is, the nonlinear absorption of laser light by LCOS will lead to a rapid rise in temperature and damage to the liquid crystal layer. This is determined by the peak power threshold;
3. Ultraviolet damage.
When the above three conditions are within the security threshold, the LCOS can be guaranteed not to be damaged.
For pulsed lasers, both the peak and average power densities of the incident laser need to be less than the threshold. For CW lasers, the average power density of the incident laser needs to be less than the threshold. The average power levels that each model can tolerate are shown in the table below.
In the table above, a spot diameter of at least 8 mm is recommendedThe power density of the aluminium reflective surface does not exceed 500 MW cm2;Other types of spot diameters are available at least 8 mm based on the highest average power. If the beam expansion is not possible, or if the above maximum value is exceeded, please contact a Hamamatsu engineer for confirmation.
Because water-cooled models cannot increase the peak power density threshold, the peak power density threshold is the same for water-cooled models and non-water-cooled models in the same band. (e.g. -03cl r, -03bl r, and -03 have the same peak power density threshold.) )
Basic parameters
Light utilization
In order to improve the utilization rate of light and minimize the loss of light energy during the modulation process, Hamamatsu's LCOS products are reflective, and the light utilization rate of the dielectric mirror model is as high as 97% or more (all wavelength bands within the parameters). Here the light utilization rate is defined as the reflectance of light reflected through the LCOS liquid crystal surface. Defined as: the average reflected light intensity as a percentage of the incident light intensity.
In the above table, the light utilization rate of 97% is applicable to all wavelengths within the parameters of the model, and the light utilization rate of the model below 90% may vary greatly with different wavelengths. (Please contact Hamamatsu engineers for the actual test wavelength.) )
Refresh rate
For X15213-03Cl CR, the response time of the liquid crystal, from the time the image signal is sent out to the completion of the liquid crystal modulation, there are two main times, one is the refresh time of the DVI signal, which is 1 60Hz=167ms;The other is the response time of liquid crystals. So the subsequent refresh rate is:
standard type = 1/(16.7ms + fall time)
For the X15223-03CL CR (sold to OEM customers only), when using the external trigger control, the refresh rate is only related to the fall time of the LCD, so:
OEM type = 1 (fall time + TTL trigger signal transmission time).
The fall time of each model is shown in the table below
First-order diffraction efficiency
The first-order diffraction efficiency, which is the true "diffraction efficiency" of LCOS, is defined by the energy of the first-order diffracted light when the grating is loaded (using LCOS as a grating) as a percentage of the energy of the zero-order light without grating. In most applications, first-order light is used, so the higher the first-order diffraction efficiency, the higher the modulation efficiency. (But for the same product, the smaller the pixel, the smaller the first-order diffraction efficiency.) So resolution and first-order diffraction efficiency are two trade-off quantities. )
In the figure, -03 represents -03 -03BL -03BR -03Cl -03Cr, and the first-order diffraction efficiency of other water-cooled models is the same as that of the same non-water-cooled model. The black dots represent the theoretical values calculated using the raster formula.
Linearity
The linearity of phase modulation is a crucial parameter in terms of the accuracy of optical modulation, and Hamamatsu is committed to pursuing high-precision modulation, and has achieved the best in the industry in terms of performance. And thanks to the excellent hardware linearity and the LUT curve of the wavelength in all parameters that come with the factory, it saves the user the trouble of calibration and further improves the modulation accuracy.
Good linearity in bright light:
Applications