SU1755243A1 - Prism telescope - Google Patents

Abstract

Usage: laser beam forming systems, laser technology, spectroscopy and communication. SUMMARY OF THE INVENTION: A telescope consists of two successive prisms with mutually perpendicular planes of main sections, each prism is made with two refracting faces and one face of total internal reflection, an A / 2 phase plate is installed between the prisms, the main directions of which form 45 &;deg; with planes of main sections of prisms. 1 il.

Description

The invention relates to optics, in particular to telescopic systems.

The invention can be used in laser beam forming systems, in laser technology, spectroscopy and communication.

Lens telescopes are known, but their disadvantage is the presence of spherical aberrations.

The closest in technical essence and achieved with the use of a positive effect to the proposed is a prism telescope consisting of two prisms with. mutually perpendicular planes of principal sections.

The disadvantage of this prism telescope is its low transmittance, which is determined by the Fresnel reflection from the faces of the prisms.

The purpose of the invention is to increase the transmission of a prism telescope.

The goal is achieved by the fact that in a prism telescope consisting of two prisms located on the same optical axis with mutually perpendicular planes of principal sections, between the prisms

a phase plate A / 2 has been installed, the main directions of which form 45 ° angles with the planes of the main sections of the prisms.

The essence of the invention is that the A / 2 plate rotates the plane of polarization of the transmitted beam between the prisms of the telescope by 90 °. Due to this, the Fresnel reflection losses from the edges of the second prism are reduced, and the transmission of the telescope increases.

The proposed technical solution meets the criterion of novelty, as it differs from the known solutions, as well as the criterion of significant differences.

The drawing shows the optical layout of the device.

The device consists of prisms 2 and 3 located on the same optical axis 1, constituting a prism telescope and phase plate A / 2 4 located between the prisms. The planes of the main sections of prisms are mutually perpendicular. The input faces of the prisms are inclined to the optical axis at the Brewster angle, the output faces of the prisms are inclined to the optical axis at an angle close to zero. Main directions

01

ate

go

s

For them, the I / 2 plates form an angle of 45 ° with the planes of the main sections of the prisms.

The invention is as follows.

Imagine a beam of natural light falling on a telescope in the form of two components polarized in the plane of incidence on the first prism (polarized ei in Fig. 1) and in the orthogonal plane (polarized ea). Let us determine the transmission of the telescope for each component.

The transmittance of the first prism for radiation with a polarization ei is equal to GB Pt r0, where tbr 1 is the transmittance of the input face for radiation polarized in the plane of incidence and incident on the face at the Brewster angle; G0 - the transmission of the output face of the prism.

In plate I / 2, the polarizations are transformed into orthogonal ones. The transmittance of the second prism for the obtained polarization is also equal to r0.

the total transmittance of the TO telescope.

The transmittance of the first prism for radiation with a polarization of e2 is equal to Gdb + r0, the total transmittance of the telescope (Gbr +70).

The transmission of the telescope for natural light is thus equal to

g (t0) 2+ (rgd go) 2,

In the event that, in order to increase the multiplicity of the telescope, N prisms are installed in the place of each prism, oriented in the same way, the transmittance of the telescope becomes equal to

Hm (Go) 2Y + (TeRHo) 2M

Passing the famous telescope under these conditions

t s (ro) 2N (rBp) N (rBp) N - O)

The increase in the transmission of the proposed telescope compared with the known

 1 -KTBR) 2N

 2 ± C) Denoting (gvr) a, we get

„1 1 +02,„

K 7G (1)

I

but

0

five

0

about

five

0

five

Function (1) is greater than one for any values of a from the interval 0 a 1, corresponding to the value of the transmission 0 Tfep 1, which confirms the proposed positive effect.

The use of the invention allows to increase the output power of the emitters using telescoping beam.

Numerical calculation for a telescope, the prisms of which are made of a material with a refractive index of n - -1.9 (Q BD - 62.2 °, GBy - 0.783) in the case of the number of prism N 1,2,4 gives an increase in transmission compared to the known telescope, respectively 1.03, 1.12, 1.52.

The increase in the transmission of the telescope for radiation polarized in the plane of incidence on the first prism is larger than for the case of natural light, and in the case of N 1,2,4 it is equal to K 1.28, 1.63, 2.66.

Claims (1)

Invention Formula A prism telescope containing two successively arranged prisms with mutually perpendicular planes of principal sections, each prism having two refracting faces and one facet of total internal reflection, characterized in that, in order to increase transmission, a phase plate is installed between the prisms I / 2, the main directions of which form angles of 45 ° with the planes of the main sections of the prisms.