Optoelectronic sampling head

Claim 2

A high speed sampling head for photoelectrons comprising a housing having a path for impinging radiation, a strip-shaped photoemissive element positioned across said path, planar photoelectron ejection means positioned in proximity to said photo-emissive element in said path, means for propagating a high speed sampling potential difference between said photoemissive element and said photoelectron ejection means, means for accelerating photoelectrons emitted by said photoemissive element in response to said incident radiation, and means for detecting said photoelectrons, whereby said ejection means constitute a microstrip ground plane for said photoemissive element.

Claim 3

The head of claim 1 wherein said photoelectron ejection means is a circular wire mesh.

Claim 4

The head of claim 1 wherein said photoemissive element is an elongated shaped strip across said optical path having a predetermined narrow dimension width relative to the spacing from said photoelectron ejection means.

Claim 5

The head of claim 3 wherein said photoemissive element is perforated.

Claim 6

The head of claim 1 wherein said means for detecting is an electron multiplier.

Claim 7

The head of claim 1 wherein a first bias potential is applied to said photoelectron ejection means whereby said photoelectron ejection means becomes negative with respect to said photoemissive element and wherein said sampling potential has a magnitude greater than said first bias potential, thereby rendering said photoelectron ejection means momentarily positive with respect to said photoemissive element.

Claim 8

An optoelectronic sampling head comprising a housing having an optical path for impinging light, a photoemissive elongated strip positioned across said optical path and supported in said housing by broadband insulated electrical feedthrough elements, an insert positionable in said housing, said insert including a photoelectron ejection ground plane and an electron path, and spacer means mounted to said insert and positioned with said insert against said housing for positioning said photoelectron ejection ground plane with predetermined spatial distance from said photoemissive strip.

Claim 9

An optoelectronic sampling head comprising a housing having an optical path for impinging light, a photoemissive elongated strip positioned across said optical path and supported in said housing by broadband insulated electrical feedthrough elements, an insert positionable in said housing, said insert including a photoelectron ejection ground plane and an electron path, and spacer means mounted to said insert and positioned with said insert against said housing for positioning said photoelectron ejection ground plane with predetermined spatial distance from said photoemissive strip.

Claim 10

The head of claim 7 wherein said photoelectron ejection ground plane is a circular wire mesh.

Claim 11

The head of claim 8 wherein said photoemissive element is perforated or semitransparent.

Claim 12

The optoelectronic sampling head of claim 7 further including means for applying a high frequency content sampling potential difference along said broadband feedthrough elements relative to said ground plane for accelerating photoelectrons emitted by said photoemissive strip toward said ground plane and along said electron path, and means coupled to said housing for receiving and detecting electrons passing along said electron path.

Claim 13

The head of claim 10 wherein said photoelectron ejection ground plane is a metallic mesh.

Claim 14

The head of claim 10 wherein said photoemissive element is perforated or semitransparent.

Claim 15

The head of claim 10 wherein said means coupled to said housing is an electron multiplier.

Claim 16

The head of claim 10 wherein a first electron retarding potential is applied to said photoelectron ejection ground plane and wherein said sampling potential exceeds said first retarding bias potential and is negative with respect to the potential of said photoelectron ejection ground plane.

Claim 17

The sampling head of claim 7, wherein said photoelectron ejection ground plane is spaced from said strip a distance up to 300 microns.

Claim 18

An optoelectronic sampling head comprising a conductive housing defining an optical path in the axial direction of said housing for impinging light, a pair of diametrically opposite apertures in said housing, insulation means sealed in said apertures, electrical leads extending through said insulating means, an elongated photoemissive strip supported on said leads inside said housing, a conductive insert positioned within said housing and having affixed thereto a perforated photoelectron ejection ground plane normal to the axis of said housing, said ground plane being spaced from said elongated strip a distance up to 300 microns in the axial direction of said housing, and electron multiplier means affixed to said housing in the optical path on the end thereof toward said ground plane, whereby said ground plane constitutes a microstrip ground plane for said strip.

Claim 19

An optoelectronic sampling head comprising a conductive housing defining an optical path in the axial direction of said housing for impinging light, a pair of diametrically opposite apertures in said housing, insulation means sealed in said apertures, electrical leads extending through said insulating means, an elongated photoemissive strip supported on said leads inside said housing, a conductive insert positioned within said housing and having affixed thereto a perforated photoelectron ejection ground plane normal to the axis of said housing, said ground plane being spaced from said elongated strip a distance up to 300 microns in the axial direction of said housing, and electron multiplier means affixed to said housing in the optical path on the end thereof toward said ground plane, whereby said ground plane constitutes a microstrip ground plane for said strip.

Claim 20

The sampling head of claim 16 wherein said housing is provided with internal threads, said insert having external threads engaging said internal threads whereby the axial position of said ground plane is adjustable, whereby said ground plane is electrically connected to said housing, and further comprising a source of a sampling potential connected to said leads, and a source of a bias potential connected to said leads.