Coherent light generators – Particular pumping means – Pumping with optical or radiant energy
Reexamination Certificate
2001-02-02
2003-06-10
Scott, Jr., Leon (Department: 2881)
Coherent light generators
Particular pumping means
Pumping with optical or radiant energy
C372S092000, C372S099000, C372S069000
Reexamination Certificate
active
06577666
ABSTRACT:
The present disclosure relates to the subject matter disclosed in International Application No. PCT/EP99/05129 (WO 00/08728) of Jul. 19, 1999, the entire specification of which is incorporated herein by reference.
The invention relates to a laser amplification system, comprising a solid-state body having a laser-active medium, a pumping radiation source for generating a pumping radiation field which passes through the solid-state body several times, an optical pumping radiation imaging means which is arranged between the pumping radiation source and the solid-state body and focuses a leg of the pumping radiation field entering the solid-state body onto the solid-state body, and at least one optical refocusing means which focuses a leg of the pumping radiation field exiting from the solid-state body onto the solid-state body again in the form of a leg entering the solid-state body and different to the outgoing leg.
A laser amplification system of this type is known, for example, from EP 0 632 551. With this laser amplification system the leg exiting from the solid-state body is merely deflected and refocused onto the solid-state body.
The disadvantage of such an optical refocusing means consists in the fact that with it the cross section of the pumping radiation field to be focused is always increased in size or considerable losses occur as a result of the fact that part of the pumping radiation field is not refocused onto the solid-state body again. Altogether, it is a problem to achieve as high a pumping radiation power density as possible in the solid-state body, in particular, under the premise that as many passes of the pumping radiation field as possible are aimed for since the absorption of the laser-active medium in the solid-state body is low with a single pass of the pumping power.
The object underlying the invention is therefore to improve a laser amplification system of the generic type in such a manner that as high a pumping radiation power density as possible can be generated in the solid-state body with as little resources as possible.
This object is accomplished in accordance with the invention, in a laser amplification system of the type described at the outset, in that the optical refocusing means reshapes the leg exiting from the solid-state body into an intermediately collimated leg and reshapes the intermediately collimated leg into a leg entering the solid-state body again and focused onto it.
The advantage of the inventive solution is to be seen in the fact that it is possible, as a result of an intermediately collimated leg being generated, to keep the diameter of the pumping light spot approximately the same size, despite refocusing, without the optical element required for the focused leg of the optical refocusing means needing to be adapted to a large beam cross section. In addition, the imaging quality during the refocusing can also be kept essentially constant.
It is particularly favorable when the pumping radiation field passes through several optical refocusing means in series one after the other since their advantages with respect to the imaging quality then become particularly evident, especially with a view to an essentially constant, maximum cross section of the pumping radiation field with an essentially equal pumping radiation spot diameter.
Purely in principle it would be conceivable with the provision of several optical focusing means not only to pump one solid-state body but rather to pump several solid-state bodies therewith.
The inventive advantages become particularly clearly evident when the incoming legs of the several optical refocusing means enter the same solid-state body so that it is, in particular, possible to pump the laser-active medium in one and the same solid-state body in the case of an essentially constant pumping radiation spot diameter with one and the same pumping radiation field under optimum utilization of the power of the pumping radiation source.
This may be realized particularly favorably when the legs entering the same solid-state body enter the same volume area of the solid-state body so that, using the fact that a constant pumping radiation spot diameter may be generated, a volume area corresponding in cross section to this pumping radiation spot diameter can also be pumped several times by the several optical refocusing means and thus a particularly high exploitation of the pumping radiation power is ensured.
One embodiment of the inventive laser amplification system which can be realized particularly favorably, especially from a geometrical point of view, provides for each optical refocusing means to reshape the leg of the pumping radiation field exiting from the solid-state body to form a first partial leg of the intermediately collimated leg, to reshape this first partial leg into a second partial leg of the intermediately collimated leg extending next to it and to form the leg entering the solid-state body from the second partial leg.
The optical refocusing means may be constructed particularly favorably with respect to the space required due to such a folding of the intermediately collimated leg into two partial legs.
Such a folding of the intermediately collimated leg may be achieved particularly favorably when each optical refocusing means has a deflection element for imaging the first partial leg of the intermediately collimated leg into the second partial leg thereof.
With respect to the additional design of the optical refocusing means no further details have been given. One advantageous embodiment, for example, provides for each optical refocusing means to have a collimating element for imaging the outgoing arm into the intermediately collimated leg. This means that the imaging of the outgoing leg into the intermediately collimated leg can be realized in a simple manner.
Furthermore, an additional embodiment provides for each optical refocusing means to have a focusing element for imaging the intermediately collimated leg into the leg entering the solid-state body.
Purely in principle it would be possible with the inventive solution to carry out the pumping of the solid-state body such that the pumping radiation source passes through the solid-state body each time free from reflection when passing from one optical refocusing means to the other optical refocusing means.
A particularly favorable configuration can, however, be achieved when a reflector is associated with a flat side of the solid-state body and the outgoing leg results due to reflection of the incoming leg at the reflector since, in this case, a twofold pumping of the solid-state body is already brought about due to the reflection.
With respect to the alignment of the individual legs in relation to the reflector no further details have so far been given. Particularly favorable conditions may be achieved when a partial leg of the intermediately collimated leg of each optical refocusing means extends parallel to a normal line to a reflection surface of the reflector.
Even more favorable imaging conditions may be created when both partial legs of the intermediately collimated leg of the optical refocusing means extend parallel to the normal line.
A leg of the pumping radiation field entering the solid-state body and the outgoing leg thereof resulting due to reflection of the leg at the reflector define a plane extending through the normal line to the reflection surface of the reflector.
The optical refocusing means are preferably designed with such a solution such that the leg of each optical refocusing means exiting from the solid-state body and the leg thereof entering the solid-state body are located in different planes extending through the normal line.
With respect to the arrangement of the collimating elements of the optical refocusing means no particular details have so far been given. One advantageous embodiment, for example, provides for the collimating elements of all the optical refocusing means to be arranged around the normal line.
In this respect, it is preferably provided for the collimating elements of all the optical ref
Erhard Steffen
Giesen Adolf
Karszewski Martin
Stewen Christian
Voss Andreas
Jr. Leon Scott
Lipsitz Barry R.
Universitaet Stuttgart Institut fuer Strahlwerkzeuge
LandOfFree
Laser amplification system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Laser amplification system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laser amplification system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3118265