I claim:
1. An external cavity tunable laser comprising:
a frequency-tuning device configured as an Acousto-optical cell including a first and a second Acousto-optical diffraction means having a narrow-band optical filtering Bragg grating.
2. The external cavity tunable laser of claim 1 wherein:
said first Acousto-optical diffraction means comprising a first Acousto-optical crystal and said second Acousto-optical diffraction means comprising a second Acousto-optical crystal.
3. The external cavity tunable laser of claim 1 further comprising:
a reflection mirror driven by a PZT assembly to reflect a beam projected from said Acousto-optical cell back to transmit therethrough again.
4. The external cavity tunable laser of claim 1 further comprising:
a first electrode connected to said first Acousto-optical diffraction means and a second electrode connected to said second Acousto-optical diffraction means.
5. The external cavity tunable laser of claim 1 wherein:
said first and second Acousto-optical diffraction means having diffraction phase gratings for intra-cavity narrow-band wavelength filtering.
6. The external cavity tunable laser of claim 3 wherein:
said first electrode is connected to an RF signal for tuning a central frequency of said narrow band Bragg grating.
7. The external cavity tunable laser of claim 3 wherein:
said second electrode is connected to a second electric source to provide a second order filtering for compensating a wavelength shift.
8. The external cavity tunable laser of claim 1 further comprising:
a collimated laser source for projecting a collimated optical signal of specific wavelength through said Acousto-optical cell.
9. The external cavity tunable laser of claim 1 wherein:
said first and second Acousto-optical diffraction means are formed as a first column and a second column respectively in a single Acousto-optical crystal.
10. The external cavity tunable laser of claim 1 wherein:
said first and second Acousto-optical diffraction means are formed as a first column and a second column respectively in a Lithium Niobate (LiNbO3) crystal.
11. The external cavity tunable laser of claim 1 wherein:
said first and second Acousto-optical diffraction means are formed as a first column and a second column respectively in a Tellurium Dioxide (TeO2) crystal.
12. The external cavity tunable laser of claim 1 wherein:
said first and second Acousto-optical diffraction means are formed as a first column and a second column respectively in a birefringent crystal having a predefined responsiveness to an radio-frequency (RF) driven signal.
13. The external cavity tunable laser of claim 1 wherein:
said first and a second Acousto-optical diffraction means having said narrow-band optical filtering Bragg grating further comprising a surface acoustic wave (SAW) grating.
14. An external cavity tunable laser comprising:
a frequency-tuning device configured as an Acousto-optical cell and a reflection means for forward and backward transmitting an optical beam through said Acousto-optical cell for generating an optical beam with zero-wavelength shift and at least twice filtered by said Acousto-optical cell.
15. The external cavity tunable laser of claim 14 wherein:
said Acousto-optical cell further comprising a first and a second Acousto-optical crystal.
16. The external cavity tunable laser of claim 14 wherein:
said Acousto-optical cell further comprising a first and a second Acousto-optical diffraction means disposed in an Acousto-optical crystal.
17. The external cavity tunable laser of claim 14 wherein:
said Acousto-optical cell further comprising a first and a second Acousto-optical diffraction columns respectively disposed in an Acousto-optical crystal.
18. The external cavity tunable laser of claim 15 wherein:
said first and second Acousto-optical cells are formed as a first column and a second column respectively in a birefringent crystal having a predefined responsiveness to an radio-frequency (RF) driven signal.
19. The external cavity tunable laser of claim 15 wherein:
said first and a second Acousto-optical cells having said narrow-band optical filtering Bragg grating further comprising a surface acoustic wave (SAW) grating.
20. An external cavity tunable laser comprising:
a frequency-tuning device configured as a non-collinear Acousto-optical cell having an acoustic wave propagates almost perpendicular to an optical transmission therethrough.
21. A method for tuning a laser comprising:
tuning said laser by a frequency-tuning device configured as a non-collinear Acousto-optical cell having an acoustic wave propagates almost perpendicular to an optical transmission therethrough.
22. The method for tuning a laser further comprising:
forming said frequency-tuning device as a first and a second Acousto-optical diffraction cells.
The claims below are in addition to those above.
All refrences to claims which appear below refer to the numbering after this setence.
1. A golf club head comprising:
a head main body made of a metal material and having a club face for striking a ball: and
a vibration absorber made of a viscoelastic material and attached to the head main body, wherein
the vibration absorber is provided with a cut having a width of not more than 1.0 mm.
2. The head according to claim 1, wherein
a surface of the vibration absorber at which the cut is opened, contacts with the head main body.
3. The head according to claim 1, wherein
a cut plane of the cut is substantially parallel with the club face.
4. The head according to claim 1, which is an iron-type golf club head comprising the head main body comprising:
a face member made of a metal material and having a back surface and a front surface forming at least part of the club face; and
a main frame made of a metal material for supporting the face member, wherein
the main frame comprises a rear wall spaced apart from the back surface of the face member, and
the vibration absorber is disposed between the back surface and the rear wall.
5. The head according to claim 4, wherein
the vibration absorber has a free part not contacting with the head main body, and
the free part extends in the space between the back surface and the rear wall.
6. The head according to claim 4, wherein
the rear wall is provided with recesses into which the vibration absorbers are fit, and
the cut is formed in a position contacting with the inner circumferential surface of recesses.
7. The head according to claim 6, wherein
each of the vibration absorbers protrudes from the recess so as to form a free part not contacting with the head main body.
8. The head according to claim 2, wherein
a cut plane of the cut is substantially parallel with the club face.