JPS6176939A - Luminescence measuring device - Google Patents

Abstract

PURPOSE:To improve the sensitivity by setting an energy distribution of an electron in a substance, to a non-balanced state by a perturbation of an electromagnetic wave, etc., irradiating a light of a wavelength corresponding to the energy between two energy levels to its substance, and measuring a luminescence by an induction light emittion. CONSTITUTION:A laser light is irradiated to a sample 3 by a continuous oscillating laser 1, and simultaneously, a laser light used for an induction light emission is irradiated to the sample 3 by changing continuously a laser oscillation wavelength by a wavelength variable continuous oscillation pigment laser 10, and an induction light emission from the sample 3 is caught by a detector 6. In this case, an induction light emission use laser light which has passed through a polarizer 11 becomes a linearly polarixed light by a plane of polarization prescribed by the polarizer 11, but the induction light emission component is not polarized. A plane of polarization of a polarizer 12 is vertical to the polarizer 11, a therefore, the induction light emission use laser light is cut off, when it passes through the polarizer 12, but a part of the induction light emission passes through and goes into the detector 6, and the induction light emission use laser light and the induction light emission are separated. Also, the induction light emission component is brought to an amplitude modulation by a modulator 13 which is driven 14, and an output signal of the detector 6 of the same frequency as said modulator is detected 8 and recorded 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a luminescence measurement device, and particularly to a luminescence measurement device that performs highly sensitive measurements.

[Background of the invention]

As a prior art, r Ilz Gat-x/Inp
7 Otoluminescence at Extremely Low Temperatures” (Mari Iijima).

Tokyo Gakugei University Bulletin, 6 Division 34 (1982) P, 3
3 to 38). Luminescence is light emitted when electrons or holes in a substance transition from a high energy state to a low energy state, and includes fluorescence and phosphorescence. In order to produce luminescence, it is first necessary to apply external energy to the substance. When this energy is electric field energy, it is called electroluminescence, and when it is light energy, it is called photoluminescence. . An example of photoluminescence will be described below. Figure 1 shows its outline. This luminescence measuring device irradiates a sample 3 with laser light using a continuous wave laser 1, and when the energy distribution of electrons in the sample 3 returns from a non-equilibrium state to an equilibrium state, light is generated by a spontaneous luminescence process. Sample 3 is placed in an extremely low temperature environment.

This emitted light is separated into spectra by a monochromator 5 collected by a lens 4 and detected by a detector 6. Since the laser beam from the continuous wave laser 1 is amplitude-modulated by the modulator 2 driven by the modulator drive device 7, the output of the detector 6 is also modulated at the same frequency as the modulator 2, and this is modulated by the lock-in amplifier. 8 performs phase sensitive detection and outputs it to the recorder 9.

In this measurement method, if the optical output intensity of the continuous wave laser 1 is increased, the emission intensity also increases, but the emission intensity is limited by the upper limit of the optical output intensity of the continuous wave laser 1. Furthermore, if the optical output intensity of the continuous wave laser 1 is increased too much, there is a concern that the sample 3 may be destroyed. Therefore, in the above conventional technology,
For P in Sl, 10'(α-1) was the detection limit.

[Purpose of the invention]

An object of the present invention is to provide a luminescence measuring device that enables highly sensitive luminescence measurement.

[Summary of the invention]

The present invention uses perturbations such as electromagnetic waves and charged particles to bring the energy distribution of electrons in a material into a non-equilibrium state, and then irradiates light with a wavelength corresponding to the two energy levels in the material to produce luminescence through stimulated luminescence. I decided to measure it.

First, the present invention will be explained in detail.

For simplicity, we consider only two quantized units of energy. Its energy levels are shown in FIG. In Figure 2, the lower energy level is NL + the higher energy level is N
h and the difference between the two is hν. shall be.

h is a blank constant.

At this time, the luminous intensity is ■. . is, 1, rn=Nh(A+B e(ν.)]...
...... (1). Here, A, B, e(ν
. ) are the spontaneous emission coefficient, stimulated emission coefficient, and externally applied frequency ν, respectively. is the energy density of electromagnetic waves. A and B are as follows.

A = 16 π” ', 'A' / 3 'oh
a ” ...””””” (2) B=2π2μ2
/3ε. h!・・・・・・・・・・・・・・・・・・
... (3) Here, go, μ, and C are the permittivity, respectively,
The transition moment is the speed of light. Therefore, the spontaneous luminescence intensity I
The fips stimulated luminescence intensity 11n is expressed by the following formula.

I,, == NhA ・・・・・・・・・・・・
・・・・・・・・・・・・・・・・・・(4)11n
= NhB e(ν.)・・・・・・・・・・・・・・・
・・・・・・・・・・・・・・・(5) The ratio R of stimulated luminescence and spontaneous luminescence is R= Itn/Iyo=Joe(ν.)/8πh・・・・・・・・・・・・...
・・・・・・・・・・・・(6) Here, λ. is the frequency ν. is the wavelength of electromagnetic waves.

The W1 cross-sectional area of the electromagnetic wave applied from the outside is 1
, the energy density of the frequency ν is e(ri), then the following equation holds true.

Episode 0 6 (sudvda=W ・・・・・・・・・・・・
(Assuming the energy density distribution of electromagnetic waves applied from outside is as shown in Figure 3, the intensity of the electromagnetic waves is determined by the cross-sectional area S.
If it is assumed to be uniform within the range, Equation (8) is established, and when this is substituted into Equation (6), the ratio R of stimulated luminescence to spontaneous luminescence becomes as expressed in Equation (9).

e(ν.) = W/ e■・Δν ・・・・・・・・・
... (8) R=, qw/sπhemsΔV ・
・・・・・・・・・・・・ (9) For the sake of simplicity, let us assume that the electromagnetic wave applied from the outside is a circular beam with a diameter of d.
The following formula is obtained.

R=λ:W/2π”d”ha・Δν ・・・・・・・・・
・ α [In the present invention, by detecting not only spontaneous luminescence as in the conventional example, but also stimulated luminescence, the ratio is taken, and in general, the magnification is expressed by equation (9), and in the case of a circular beam, (II It becomes possible to measure the sensitivity at the magnification shown in 2.

FIG. 4 shows the value of R when W = 100 mv and d = vm. Δν as A? It was made into a parameter. Δν=
= IGHz, an improvement in sensitivity of two orders of magnitude or more can be achieved.

[Embodiments of the invention]

FIG. 5 shows an embodiment of the luminescence measuring device of the present invention. In this embodiment, a wavelength tunable continuous wave dye laser 10,
It is characterized by the provision of polarizers 11 and 12 and the provision of a modulator 13.

A continuous wave laser 1) irradiates the sample 3 with laser light.

At the same time, the sample 3 is irradiated with a laser beam used for stimulating light emission while continuously changing the laser oscillation wavelength by the wavelength tunable continuous wave dye laser 10, and the stimulated light emission from the sample 3 is captured by the detector 6.

At this time, the laser light from the wavelength tunable continuous wave dye laser 10 and the stimulated light emission thereby enter the detector 6 with the same wavelength, phase, and direction. For this reason, the two components of light must be separated by some method. Therefore, polarizers 11 and 12 are placed in the optical path of the wavelength tunable continuous wave dye laser 10, and their polarization planes are set at right angles to each other.

The stimulated light emission laser beam that has passed through the polarizer 11
It becomes linearly polarized light with the polarization plane defined by , but the stimulated emission component is polarized. Since the polarization plane of the polarizer 12 is perpendicular to the polarizer 11, the stimulated emission laser beam is blocked when it passes through the polarizer 12, but a part of the stimulated emission passes and is detected by the detector 6.
At the beginning, the laser light for stimulating light emission and the stimulating light emission are separated.

Furthermore, the stimulated emission component is amplitude-modulated by a modulator 13 driven by a modulator drive device 14, and the output signal of the detector 6 having the same frequency is subjected to phase-sensitive detection by a lock-in amplifier and output to a recorder 9.

FIG. 6 shows another embodiment of the luminescence measuring device of the present invention. This embodiment is characterized by the provision of wavelength variable continuous wave pixel laser lO1 modulators 15 and 16 and an integrator 18. First, the continuous wave laser 1 irradiates the sample 3 with laser light. At the same time, the sample 3 is irradiated with a laser beam used for stimulating light emission while continuously changing the laser oscillation wavelength by the wavelength tunable continuous wave dye laser 10, and the stimulated light emission from the sample 3 is captured by the detector 6. At this time, since the laser light from the wavelength tunable continuous wave dye laser 10 and the stimulated light emission thereof enter the detector 6 with the same wavelength, phase, and direction, it is necessary to separate the two components of light by some method. For this purpose, a modulator 15 is placed in the optical path of the continuous wave laser 1, and a modulator 6 is placed in the optical path of the wavelength tunable continuous wave dye laser 10, and each modulates the same frequency.

An example of the timing at this time is shown in FIG. Laser light intensity of continuous wave laser 1 and wavelength tunable continuous wave dye laser 1
There is always a time when the laser light intensity of 0 exists and a time when only the laser light intensity of the wavelength tunable continuous wave dye laser 10 exists. At this time, the light intensity reaching the detector 6 changes as shown in FIG. At time t, two components, the laser light and stimulated emission from the wavelength tunable continuous wave dye laser 10, enter the detector 6, and at time t! Now, wavelength tunable continuous wave dye laser 1
Only the zero laser light reaches the detector 6. Therefore, the output of the detector 6 is input to a two-channel MEX force-integrator 18, and the output is inputted to the first channel at time t, and inputted to the first channel at time 1. When , the signal is acquired on the second channel, the data on the second channel is subtracted from the data on the first channel, and the signal is sent to the recorder 9.
output to capture only the stimulated luminescence intensity.

In this embodiment, a continuous wave laser is used to bring the energy distribution in the sample cage into a non-equilibrium state, but other electromagnetic waves or charged particles may also be used.

〔Effect of the invention〕

According to the present invention, the energy distribution of the υ material's inner cage is changed to a non-equilibrium state KL by perturbation of electromagnetic waves, charged particles, etc., and by stimulating light emission by applying light of a wavelength corresponding to between two energy levels of the material. By measuring luminescence, we were able to obtain a significant improvement in sensitivity.

[Brief explanation of drawings]

Figure 1 is a diagram of a conventional example, Figure 2 is an explanatory diagram of energy levels, Figure 3 is a diagram showing the relationship between frequency and energy density,
FIG. 4 is a diagram showing the relationship between wavelength and ratio R for detailed explanation of the present invention, FIG. 5 is a diagram of an embodiment of the present invention, FIG. 6 is a diagram of another embodiment of the present invention, and FIG. The figure is a diagram showing the relationship between laser input intensity and time. 1... Continuous wave laser, 3... Sample, lO... Wavelength tunable continuous wave dye laser, 11.12... Polarizer,
13...Modulator, 6...Detector, 8...Lock-in amplifier, 9...Recorder, 15.16...Modulator,
18... Gexcar integrator. Agent Patent Attorney Tadashi Akimoto Actual Fig. 1 Fig. 2 Fig. 3 Nanashiki υ Fig. 4 1 (pm) Fig. 5 Fig. 6 Fig. 7 Inter-office procedure Neho Masashi: (Volunteer) 1988 February 20th

Claims (1)

[Claims] 1. A first electromagnetic wave source (or charged particle source) that irradiates a sample to be measured with a first electromagnetic wave (or charged particles), and a second electromagnetic wave that generates a second electromagnetic wave. a first polarizer provided on the second electromagnetic wave path and irradiating the sample with its output; and a first polarizer provided on the measurement path of the light emitted from the sample and perpendicular to the first polarizer. a second polarizer having a plane of polarization, a modulator provided on the output side of the second polarizer, a monochromator that separates the output of the modulator, and a detection means that captures and detects the output of the monochromator. A luminescence measuring device consisting of: 2. A first electromagnetic wave source (or charged particle source) and a first modulator that is installed on the path of the electromagnetic wave (charged particles) generated by the first electromagnetic wave source and irradiates the sample to be measured with its output. a second electromagnetic wave source; a second modulator that is installed on the path of the electromagnetic waves generated by the second electromagnetic wave source and irradiates the sample to be measured with its output; A luminescence measuring device comprising a monochromator and a detection means for receiving and detecting the output of the monochromator. 3. The first electromagnetic wave (or charged particles) and the second electromagnetic wave that are irradiated onto the sample through the first modulator and the second modulator overlap each other during the irradiation time period and only the second electromagnetic wave is irradiated. 3. The luminescence device according to claim 2, wherein the luminescence device is irradiated with a time period of individual irradiation.