Apparatus for measuring magnitude of deflected probe beam signal generated by laser-induced breakdown and method of measuring size of nanoparticles using frequency distribution curve of magnitude of probe beam deflection signal

A method of measuring a size of nanoparticles using a frequency distribution curve of a magnitude of a deflected probe beam signal generated by laser-induced breakdown, comprising:

• a) generating laser-induced plasma by causing a pulse laser beam to be incident on a sample cell, which contains a standard nanoparticle having a known size, in a Z-axis direction so that the pulse laser beam is focused on an internal location of the sample cell, and causing a probe beam to be incident on the sample cell in a Y-axis direction perpendicular to a travel path of the pulse laser beam so that the probe beam passes through an internal location of the sample cell, spaced apart in an X-axis direction from a focus of the pulse laser beam by a predetermined distance;
• b) measuring signals of the probe beam, deflected by a laser-induced shock wave generated by the laser-induced plasma, using a photodiode;
• c) adjusting the focus of the pulse laser beam so that two signals, having collided against two walls of the sample cell located on an X-Y plane of the sample cell and then having reached the probe beam, among the deflected probe beam signals measured at b), overlap each other;
• d) obtaining symmetrical frequency distributions of magnitudes of a first deflected probe beam signal, appearing when the laser-induced shock wave directly reaches the probe beam, and a second deflected probe beam signal obtained at c), among the deflected probe beam signals measured at b), using a gate integrator;
• e) performing curve fitting on the symmetrical frequency distribution of the magnitude of the first deflected probe beam signal obtained at d) to form a shape of a Gaussian function, and obtaining a peak and a full-width at half-maximum value from the curve-fitted distribution curve;
• f) repeating a) to e) with respect to a standard nanoparticle having a size differing from that of the standard nanoparticle used at a) to e);
• g) obtaining calibration curves by causing peaks and full-width at half-maximum values of curve-fitted distribution curves, respectively obtained at e) and f), to correspond to the sizes of the standard nanoparticles, respectively;
• and
• h) performing a) to e) with respect to an unknown particle, a size of which is unknown, and determining a size of the unknown nanoparticle using the calibration curves obtained at g).

A method of measuring a size of nanoparticles using a frequency distribution curve of a magnitude of a deflected probe beam signal generated by laser-induced breakdown, comprising:

• a) generating laser-induced plasma by causing a pulse laser beam to be incident on a sample cell, which contains a standard nanoparticle having a known size, in a Z-axis direction so that the pulse laser beam is focused on an internal location of the sample cell, and causing a probe beam to be incident on the sample cell in a Y-axis direction perpendicular to a travel path of the pulse laser beam so that the probe beam passes through an internal location of the sample cell, spaced apart in an X-axis direction from a focus of the pulse laser beam by a predetermined distance;
• b) measuring signals of the probe beam, deflected by a laser-induced shock wave generated by the laser-induced plasma, using a photodiode;
• c) adjusting the focus of the pulse laser beam so that two signals, having collided against two walls of the sample cell located on an X-Y plane of the sample cell and then having reached the probe beam, among the deflected probe beam signals measured at b), overlap each other;
• d) obtaining symmetrical frequency distributions of magnitudes of a first deflected probe beam signal, appearing when the laser-induced shock wave directly reaches the probe beam, and a second deflected probe beam signal obtained at c), among the deflected probe beam signals measured at b), using a gate integrator;
• e) performing curve fitting on the symmetrical frequency distribution of the magnitude of the second deflected probe beam signal obtained at d) to form a shape of a Gaussian function, and obtaining a peak and a full-width half-maximum value from the curve-fitted distribution curve;
• f) repeating a) to e) with respect to a standard nanoparticle having a size differing from that of the standard nanoparticle used at a) to e);
• g) obtaining calibration curves by causing peaks and full-width at half-maximum values of curve-fitted distribution curves, respectively obtained at e) and f), to correspond to the sizes of the standard nanoparticles, respectively;
• and
• h) performing a) to e) with respect to an unknown particle, a size of which is unknown, and determining a size of the unknown nanoparticle using the calibration curves obtained at g).