Method and device for producing radio frequency waves

• US 20040021056A1
• Filed: 06/24/2003
• Published: 02/05/2004
• Est. Priority Date: 09/08/2000
• Status: Active Grant

• Current Assignee: Max-Planck-Gesellschaft Zur Foerderung Der Wissenschaften e.V. (Max-Planck-Gesellschaft zur Frderung der Wissenschaften e)
• Original Assignee: Max-Planck-Gesellschaft Zur Foerderung Der Wissenschaften e.V. (Max-Planck-Gesellschaft zur Frderung der Wissenschaften e)
• Inventors: Udem, Thomas, Hansch, Theodor, Holzwarth, Ronald
• Granted Patent: US 7,026,594 B2
• Time in Patent Office: Days
• US Class Current: 250/206
• CPC Class Codes: H01S 3/13 Stabilisation of laser output parameters, e.g. frequency or amplitude
• CPC Class Codes: H01S 3/1305 Feedback control systems

Abstract

The invention relates to a method for producing radio frequency waves, whereby a pulse laser for producing light pulses having a predetermined spectrum of frequency modes and a predetermined recurrence frequency is operated. The light pulses of the pulse laser are detected by means of a detector device, and corresponding electrical output signals forming the radio frequency signals are produced. Said pulse laser is actuated in a stabilized manner by means of an optical reference signal in such a way that the recurrence frequency of the light pulse is fixed. The invention also relates to a radio frequency generator for implementing said method.

Claims

1. A method for the production of radio frequency waves, in which a pulse laser (10) is operated for the production of light pulses with a predetermined spectrum of frequency modes and a predetermined repetitive frequency, having a first detector (11) which captures light pulses of the pulse laser (10) and wherein corresponding electrical output signals are generated, which form the radio frequency waves, therein characterized, in that the pulse laser (10), stabilized with an optical reference signal, is operated in such a manner that the repetitive frequency of the light pulse is fixed.

2. A method in accord with claim 1, in which the frequency stabilization is carried out by a control circuit (30), in which, the repetitive frequency of the pulse laser (10) is adjusted, dependent upon an oscillatory signal captured by a second detector (31) from at least one first frequency mode of the light pulse of the pulse laser, and from an optical reference frequency, which forms the optical reference signal.

3. A method in accord with claim 2, wherein the optical reference frequency is produced by a stabilized reference laser (32).

4. A method in accord with claim 2, in which the optical reference signal is produced with a reference damping cell (32), in which an atomic transition is incited under predetermined conditions.

5. A method in accord with claim 1, wherein the frequency stabilization is executed by a control circuit (30), in which the repetitive frequency of the pulse laser (10) is fixed, dependent upon a fluorescent signal emanating from a reference damping cell (32) which is captured by a second detector (31), wherein an atomic transition is optically excited under predetermined conditions.

6. A method in accord with one of the foregoing claims, wherein a diode-pumped, solid state laser, or a ring laser is employed as a pulse laser (10).

7. A method in accord with one of the foregoing claims, in which a broadening of the spectrum of the frequency modes of the light pulse is done by means of self-phase modulation.

8. A method in accord with one of the foregoing claims, in which is provided a stabilization of the offset-frequency of the frequency components of the light pulse produced by the pulse laser (10).

9. A radio frequency generator, which comprises:

a pulse laser (10) for the production of light pulses with a predetermined spectrum of frequency modes and a predetermined repetitive frequency and

a first detector (20), which is designed to produce, from the light pulses of the pulse laser, electrical output signals, which form the radio frequency waves,

therein characterized, in that a circuit (30) for the frequency stabilization of the pulse laser (10) relative to an optical reference signal is provided, with which the repetitive frequency of the light pulse can be fixed.

10. A radio frequency generator in accord with claim 9, in which the pulse laser (10) has a device for the establishment of the repetitive frequency and the frequency stabilization circuit (30) contains a second detector (31) and a reference frequency generator (32), wherein the second detector is designed for the purpose of capturing simultaneously the light pulse of the of the pulse laser (10) and the optical reference signal as a reference frequency, and to produce an oscillatory signal, with which the equipment can be made controllable for the fixing of the repetitive frequency.

11. A radio frequency generator in accord with claim 10, in which the reference frequency generator (32) is comprised of a stabilized continuous wave laser.

12. A radio frequency generator in accord with claim 10, wherein the pulse laser (10) possesses an element for the fixing of the repetitive frequency and the frequency stabilization circuit (30) has a second detector (31) and an optical reference cell for the production of the optical reference signal, wherein the said second detector (31) is designed for the purpose of capturing the optical reference signal as a fluorescent signal of the reference cell (32) and to produce an output signal, with which the said element for the fixing of the repetitive frequence is controllable.

13. A radio frequency generator in accord with one of the claims 9 to 12, in which the pulse laser (10) consists of a diode pumped solid state laser or a ring laser.

14. A radio frequency generator in accord with one of the claims 9 to 13, in which an apparatus (11) is provided for the broadening of the spectrum of the frequency modes of the light pulse.

15. A radio frequency generator in accord with claim 14, in which the broadening apparatus (11) is constructed of an optical fiber.

16. A radio frequency generator in accord with one of the claims 9 to 15, in which is provided the circuit 40 for the frequency stabilization of the pulse laser (10), whereby the frequency components of the light pulses can be fixed.

17. The use of a frequency stabilized pulse laser for the production of radio frequency waves.