Acoustic microscope and method

An acoustic microscope, comprising:

• (a) a laser having an output of focused optical light energy, said light being focused on a microscopic portion of an object of interest so that the object absorbs the energy, thermally expands and generates acoustic waves which are propagated therefrom;
• (b) an acoustic lens focused on the object of interest and positioned so that the acoustic lens and the laser are confocal and the object of interest is located at the common focal point, said acoustic lens collimates only the incident acoustic waves propagated from the object;
• (c) an acoustic wave transducer connected to the acoustic lens for detecting the acoustic waves propagated from the microscopic portion of the object of interest, said acoustic wave transducer being sensitive to acoustic waves having frequencies greater than about 100 MHz;
• (d) means connected to the object of interest and the acoustic lens for moving one of either the object or the lens with respect to the other so that the object of interest is scanned in a raster pattern;
• and
• (e) means connected to the detecting means and the moving means for recording the detected acoustic waves and the corresponding raster position of the object of interest so that a visual image of the object can be obtained.

An acoustic microscope, comprising:

• (a) a first laser having an output of focused optical light of frequency .nu..sub.1 ;
• (b) a second laser having a modulated output of focused optical light at a frequency .nu..sub.2, both said lasers being focused on a microscopic portion of an object of interest and said frequencies being such that .vertline..nu..sub.1 -.nu..sub.2 .vertline. equals the Raman frequency vibration mode of one of the constituents of the object;
• (c) an acoustic lens focused on the object and positioned so that the acoustic lens and the lasers are confocal and the object is at the common focal point, said acoustic lens collimates the incident acoustic waves from the object;
• (d) an acoustic wave transducer connected to the acoustic lens for detecting the acoustic waves propagated from the object of interest;
• (e) means connected to the object of interest and the acoustic lens for moving one of either the object or the lens with respect to the other so that the object of interest is scanned in a raster pattern;
• and
• (f) means connected to the detecting means and the moving means for recording the detected acoustic waves and the corresponding raster position of the object of interest so that a visual image of the object can be obtained.

An acoustic microscope, comprising:

• (a) an electric current generator having a periodic output I (.omega.) of frequency .omega., the generator being connected to an electrical circuit for passing current through an object of interest, said current causing the object of interest to be periodically heated so that acoustic waves of a corresponding frequency are generated and propagated from the object;
• (b) an acoustic lens focused on the object of interest and positioned so that the focal point of the lens is coincident with the object of interest, said acoustic lens collimates the incident acoustic waves from the object;
• (c) an acoustic wave transducer connected to the acoustic lens for detecting the acoustic waves propagated from the object of interest, said acoustic wave transducer being sensitive to acoustic waves having frequencies greater than about 100 MHz;
• (d) means connected to the object of interest and the acoustic lens for moving one of either the object or the lens with respect to the other so that the object of interest is scanned in a raster pattern;
• and
• (e) means connected to the detecting means and the moving means for recording the detected acoustic waves and the corresponding raster position of the object of interest so that a visual image of the object can be obtained.

An acoustic method for microscopically imaging an object of interest, comprising the steps of:

• (a) exciting an object of interest by heating so that acoustic waves are generated and propagated therefrom;
• (b) detecting the acoustic waves propagated only from a microscopic portion of the object of interest having frequencies greater than about 100 MHz;
• (c) translating one of either the object of interest or the detecting means with respect to the other so that the microscopic portion of the object of interest is scanned in a raster pattern;
• and
• (d) recording the detected acoustic waves and the corresponding raster position of the object of interest so that a visual image of the object can be obtained.

An acoustic method for microscopically imaging an object of interest, comprising the steps of:

• (a) heating an object of interest in a cyclical manner so that the object of interest expands and contracts in response thereto and acoustic waves are generated and propagated thereby;
• (b) focusing an acoustic lens on microscopic portions of the heated object of interest so that only the acoustic waves propagated therefrom are collimated;
• (c) detecting acoustic waves having frequencies greater than about 100 MHz and converting said waves into corresponding electrical signals;
• (d) translating one of either the object of interest or the acoustic lens with respect to the other so that the object of interest is scanned in a raster pattern;
• and
• (e) recording the electrical signals and the corresponding raster position of the object of interest so that a visual image of the object can be obtained.

An acoustic method for spectrographically analyzing objects of interest, comprising the steps of:

• (a) heating an object of interest with both cyclical and amplitude modulated electromagnetic radiation so that acoustic waves are generated and propagated therefrom;
• (b) varying the amplitude modulation of the electromagnetic radiation so that acoustic waves of correspondingly varying frequency are generated and propagated from the object;
• (c) detecting only the acoustic waves propagated from a microscopic portion of the object of interest having frequencies greater than about 100 MHz;
• and
• (d) measuring the change in intensity of the detected acoustic waves corresponding to the variation in the electromagnetic radiation so that the absorption spectrum of the object of interest is observed and thereby spectrographically analyzing the object of interest.

An acoustic method for determining the Raman frequency mode of an object of interest, comprising the steps of:

• (a) focusing laser light having an optical frequency .nu..sub.1 on a microscopic portion of an object of interest;
• (b) focusing modulated laser light having an optical frequency .nu..sub.2 on the same microscopic portion of the object;
• (c) varying the absolute value of the difference between the two optical frequencies (.vertline..nu..sub.1 -.nu..sub.2 .vertline.) so that the molecules in the object of interest become excited and acoustic waves are propagated therefrom;
• (d) detecting the acoustic waves propagated from the microscopic portion of the object;
• and
• (e) measuring the change in intensity of the detected acoustic waves corresponding to the variation in said absolute value so that the Raman spectra of the microscopic portion of the object of interest is determined along with the Raman frequency mode.

An acoustic microscope, comprising:

• (a) a first laser having an output of focused optical light of frequency .nu..sub.1 ;
• (b) a second laser having a modulated output of focused optical light at a frequency .nu..sub.2, both said lasers being focused on a microscopic portion of an object of interest, said frequency .nu..sub.1 corresponding to an electronic excited state of an atom in the object of interest so that the atom is transferred from a ground state to an excited state;
• (c) an acoustic lens focused on the object and positioned so that the acoustic lens and the lasers are confocal and the object is at the common focal point, said acoustic lens collimates the incident acoustic waves from the object;
• (d) an acoustic wave transducer connected to the acoustic lens for detecting the acoustic waves propagated from the object of interest;
• (e) means connected to the object of interest and the acoustic lens for moving one of either the object or the lens with respect to the other so that the object of interest is scanned in a raster pattern;
• and
• (f) means connected to the detecting means and the moving means for recording the detected acoustic waves and the corresponding raster position of the object of interest so that a visual image of the object can be obtained.

An acoustic method for determining the atomic constants of an object of interest, comprising the steps of:

• (a) focusing laser light having an optical frequency .nu..sub.1 on a microscopic portion of an object of interest;
• (b) focusing modulated laser light having an optical frequency .nu..sub.2 on the same microscopic portion of the object, said frequency .nu..sub.1 corresponding to an electronic excited state of an atom in the object of interest;
• (c) transferring said atom from a ground state to an excited state by use of said laser light so that acoustic waves are propagated therefrom;
• (d) detecting the acoustic waves propagated from the microscopic portion of the object;
• and
• (e) translating one of either the object of interest or the detecting means with respect to the other so that the object of interest is scanned in a raster pattern;
• and
• (f) recording the detected acoustic waves and the corresponding raster position of the object of interest so that a visual image of the object can be obtained.