Select finite element analysis/parameter input and start (FEA/ parameter input &; Finite element analysis begins.
Code), you can open the crystal, pump beam and material parameters window (. Crystals, pump beams and materials
Parameter window. The main part of the window is a dialog box with six tabs. They are introduced as follows,
Model (model)
There are eight options to choose different pumping modes and crystal geometries.
6? 1 round rod, (double-ended) end pumping
6? 1 round rod, the pump light shows a flat-topped Gaussian distribution along the Z axis and a super-Gaussian distribution perpendicular to the Z axis.
6? 1 plate, (double-ended) end pumping
6? 1 slab, the pump light shows a flat-topped Gaussian distribution along the Z axis and a super-Gaussian distribution perpendicular to the Z axis.
6? 1 round rod, side pumping
6? 1 slat, side pumping, including sandwich structure.
6? 1 round rod, numerical input pump light distribution
6? 1 plate, numerical input pump light distribution
In the box below the option box, you can enter the length, diameter or width and height of the crystal. For plate crystals, the end face also
May be inclined, in which case the length of the crystal is the distance between the centers of two end faces. The end face of the crystal is parallel to the long side of the crystal.
The number of z directions, the coordinate origin is located in the center of the leftmost end face. The end face rotates around an axis parallel to the Y axis, and the rotation angle is between the end face and the Y axis.
The positive included angle of Z axis, 90 indicates that the end face is perpendicular to Z axis, and the negative included angle indicates that the included angle between the end face and Z axis is greater than 90. Complete finite element method
After analysis and calculation, select the "Finite Element Analysis/3D Visualization Tool" option in the menu, open the 3D view, and then click.
In which the origin of the coordinate system can be displayed.
Pump light
Here you can enter the pump power and parameters to define the distribution of pump light. The content of this input data frame depends on what you have.
The selected structure.
Terminal pump
In the case of end pumping, the intensity distribution of the pump beam, that is, the absorbed pump power density [unit: Watt/m3 milli].
M, (w/mm 3)] is simulated by super Gaussian function. You can choose rotational symmetry or X-Y symmetry. The pump beams can be respectively from the left end face.
Or the right end face, or both ends. In the incident power value box on the page, respectively define.
When there are no incident beams, the total power of each beam must be set to zero. Click one of the incident power number boxes and the above parameters.
Several frames are automatically arranged in the left or right beam.
High-hat pump light distribution in z direction
In the z direction)
This input type is very useful when the user knows the approximate distribution of pump light, such as flash pump or side pump. Assuming that the distribution of pump light in a specific region in Z direction is uniform, this specific region can be defined by the doped region on the registered data card, and the lateral distribution can also be described by the super-Gaussian distribution with rotational symmetry and X-Y symmetry. For this type, finite element analysis (FEA) is used to achieve standardization. Therefore, in this case, the pump power input in the total pump power data frame corresponds to the integral of the pump light distribution on the whole crystal, even if the distribution on the crystal side surface is not zero.
Lateral sucker rod
In this structure, the input of most pump parameters is obvious on its registered data card. wrong
There is a sleeve outside the round bar, there is flowing liquid between the round bar and the sleeve, and there is a reflector outside the sleeve, and the radius is not certain.
The meaning is the distance from the crystal axis, so it is not necessarily concentric with the crystal. The length of the refrigeration part can be on the data card.
Is defined in the bounding box of. The total pump power is the pump power of all the pump diodes.
The sum of. The length of diode linear array refers to the length of a single linear array along its slow axis. Diode; A person who lacks dialectical thinking
The divergence of the strip in the slow axis direction is not considered, so the selection of the length should approximately include the influence of divergence. If you put it around the crystal,
If there are multiple groups of diode bars, these diode bars will be automatically staggered by 360/2n, where n is the number of diode bars around the crystal.
Only when the diode array is placed symmetrically with respect to the circular array, this automatic uniform spacing makes sense. If you don't need to stagger each other, it is parallel.
Enter "1" in the data box for the number of diodes in the axial direction of the crystal.
Then, the number of diodes in the axial direction is multiplied by the length value of the diode bar and input.
The length of the diode bar is in the data frame. X-coordinate (X-coordinate) of the intersection point of the pump beam.
The intersection of pump beam) allows that intersection of each pump beam in the radiation direction to move to the crystal axis.
In addition, for example, to compensate for the asymmetric heat distribution pumped by two diode bars. The full angular width (FWHM) at half the maximum value is used for
Calculate the Gaussian far-field divergence angle of the diode along the fast axis direction, that is, the angle when the intensity drops to 1/e 2. Now the calculation assumes that along the fast axis.
The super-Gaussian intensity distribution with an index of 4 in the direction will soon provide users with direct input of the super-Gaussian index on the graphical user interface (GUI).
Value.
Press the show pump beam button to see the cross section of the pump beam perpendicular to the crystal axis.
The cross-sectional view shows that the pump beam starts from the diode, passes through the sleeve, the crystal, then passes through the sleeve, and finally is reflected back and passes through the sleeve again.
Distribution of tubes, crystals and sleeves on crystals. The calculation of this number takes into account the refractive index and curvature of all crystals, sleeves and reflectors.
noodle The coherent pump beam is considered in Gaussian algorithm, so the result may be better than that of ray tracing software before the first reflection.
Tracking code) is better. Since the phase difference becomes very important after the first reflection, this method can only emit light.
An approximate result of the reflection part of the beam, for which a program is installed to slightly broaden the pump beam with a diameter less than 40 microns.
Compared with the calculation results of line drawing software, the two are in good agreement, with only a few percentage points difference. In the cross-sectional view of the pump light shape, the element
The term 1 1, that is, the cylindrical surface of the round rod, represents the pattern when the second reflected pump beam returns through the crystal. Secondary reflection is not considered in the calculation of pump light distribution, but it can be included as needed.
Of course, the above calculation method can also be used when there is no liquid flow sleeve between the crystal rod and the diode and the crystal rod is directly irradiated.
Conditions. In this case, the thickness of the liquid flow sleeve should be set very small, and the refractive index of the sleeve and the refrigerant must be set to be the same as that of the diode.
The refractive index of the cooling medium between the round rods is equal.
Similarly, the "Show pump light distribution" button can be used to show the difference along the z axis.
Distribution of absorbed pump light on the same cross section.