Optical: systems and elements – Single channel simultaneously to or from plural channels – By refraction at beam splitting or combining surface
Reexamination Certificate
2001-03-29
2003-02-04
Epps, Georgia (Department: 2873)
Optical: systems and elements
Single channel simultaneously to or from plural channels
By refraction at beam splitting or combining surface
C359S639000, C359S618000, C385S146000
Reexamination Certificate
active
06515802
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims priority of a German patent invention DE 100 16 361.0 filed Apr. 3, 2000 which is incorporated by reference herein.
FIELD OF THE INVENTION
The invention concerns an optical arrangement for at least partial spectral selection of light components from a polychromatic light beam.
BACKGROUND OF THE INVENTION
In many optical applications, it is necessary to block or attenuate specific spectral components, and in turn not to block or attenuate other light components, of a polychromatic light beam that has spectrally different light components. A polychromatic light beam or polychromatic light bundle is thereby selectively adjusted in terms of its spectrum.
In confocal scanning microscopy, for example, multiple-line lasers, inter alia, are used to illuminate the specimen, and it would be desirable to regulate the light outputs or light intensities of the individual lines separately from one another, and selectably to block individual spectral light components. Acousto-optical modulators, inter alia, are used for this purpose.
The acousto-optical modulators used hitherto are, on the one hand, very flexible; but on the other hand they have the great disadvantage of being very complex in terms of construction and electronic control, and for these and other reasons they are very expensive.
SUMMARY OF THE INVENTION
It is therefore the object of the present invention to describe an optical arrangement of the kind cited initially for at least partial spectral selection of light components from a polychromatic light beam in which multifarious spectral selection capabilities are realized with means of simple design.
The above object is achieved by an optical arrangement for at least partial spectral selection of light components from a polychromatic light beam. The arrangement comprising: a dispersive medium for spatial spectral spreading of the polychromatic light beam and thereby defining a plurality of individual light bundle, and an attenuation means for at least partial attenuation of the intensity of one or more light bundles.
Additionally the above object is achieved by an arrangement for at least partial spectral selection of light components from a polychromatic light beam. The arrangement comprising: a dispersive medium for spatial spectral spreading of the polychromatic light beam wherein the dispersive medium is a four-prism arrangement, the dispersive medium defines a plurality of individual light bundles, and an attenuation means for at least partial attenuation of the intensity of one or more light bundles.
A further arrangement solve the above problem. The arrangement comprising: a dispersive medium for spatial spectral spreading of the polychromatic light beam and thereby defining a plurality of individual light bundles, the dispersive medium is configured as a parallelepipedal glass member with two parallelogram-shaped side surfaces and an attenuation means for at least partial attenuation of the intensity of one or more light bundles.
What has been recognized first of all according to the present invention is that multifarious spectral selection capabilities can be implemented not only by way of complex acousto-optical modulators. Further according to the present invention, an arrangement which makes possible a quasi-mechanical selection of individual light bundles is made available for this purpose. What is made available for this purpose firstly is a dispersive medium for spatial spectral spreading of the polychromatic light beam into individual light bundles. After this spreading, a definable partial or complete attenuation of the intensity of one or more definable light bundles then takes place by means of an attenuation means. Both an intensity reduction and a complete blocking of a light bundle are thus possible. The term “light bundle” refers to a light beam that exhibits one or more discrete wavelengths or a wavelength band. A complex electronic control system is usually not necessary in the context of the arrangement according to the present invention. This makes the assemblage considerably simpler and less expensive.
The optical arrangement according to the present invention consequently makes available an arrangement in which multifarious spectral selection capabilities are realized with means of simple design.
In a concrete and very simple embodiment of the optical arrangement, the dispersive medium could have a prism. Such prisms have been known for some time and are usually very easy to manufacture.
The prism could be rotatable, within a plane spanned by the spread light bundle, about an axis extending perpendicular to the plane. This makes possible a spatial displacement of the light bundles. This displacement can be used, in interaction with the attenuation means, for partial or complete attenuation of one or more light bundles. Displacement in the region of a stop as the attenuation means might be imagined in this context.
In particularly practical fashion, the prism could have placed after it an optical system that preferably has a lens. This makes it possible to guide the spread light bundles in parallel fashion.
In a further embodiment, the dispersive medium could have a four-prism arrangement. Concretely, the four-prism arrangement comprise a first and a second prism pair arranged in mirror symmetry with respect to one another. The light bundle that is spectrally spread and diverged by the first prism is then collimated by the second prism of the prism pair. The first and second prism pair could moreover be arranged in mirror symmetry with respect to a line perpendicular to the propagation direction of the light bundles. The second prism pair serves, in this context, to recombine the light bundles. Between the first and second prism pair, the manipulation in terms of blocking and attenuation by means of the attenuation means is performed. If, after passing through the arrangement, the light is to pass through a stop or is to be coupled into a light-guiding fiber, it is essential to ensure that the spatial spectral spreading is completely annulled. Otherwise spectral differences in loss levels can occur at the stop or upon coupling into the fiber. It is particularly favorable in this context if the second prism pair is aligned in exact mirror symmetry with respect to the first prism pair.
In a further embodiment, the dispersive medium could have a glass member. The glass member could, in particular, be configured parallelepipedally, with two parallelogram-shaped side surfaces, or trapezoidally. In the interest of reliable recombination of the spread light bundles, a first and second glass member are arranged in mirror symmetry with respect to a line perpendicular to the propagation direction of the light bundles. This kind of arrangement of the first and second glass member reduces the stringent requirements in terms of alignment accuracy. Whereas a tilting of one prism results in an angular error (and, if the tilted prism is one of the inner prisms, in a beam offset which in turn interferes with correct spectral recombination), a tilting of one of the glass members results only in a parallel offset, which only slightly degrades the spectral properties of the arrangement. In particular, coupling into a light-guiding fiber after the arrangement is not influenced, since the collimated recombined light bundles are focused by the coupling-in optical system onto the fiber end even in the presence of a beam offset. In this fashion, an embodiment of the optical arrangement with two the first and second glass member makes available a simplified optical arrangement.
In a further alternative embodiment, the dispersive medium could have a grid.
In the interest of reliable and at the same time simple selection of light components from a polychromatic light beam, the attenuation means could have one or more stops combined with one another. Reliable mechanical influence on the light bundle or bundles is thereby achieved.
Concretely, the stop or stops could be implemented by way of at least one stop wheel
Epps Georgia
Leica Microsystems Heidelberg GmbH
Simpson & Simpson PLLC
Thompson Timothy J
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