Nanometer scale quantum thermometer
An approach to nanoscale thermometry that utilizes coherent manipulation of the electronic spin associated with nitrogen-vacancy (NV) color centers in diamond is disclosed. The methods and apparatus allow for detection of temperature variations down to milli-Kelvin resolution, at nanometer length scales. This biologically compatible approach to thermometry offers superior temperature sensitivity and reproducibility with a reduced measurement time. The disclosed apparatus can be used to study heat-generating intracellular processes.
1. A method of measuring temperature of a heat source comprising:
providing an electron spin system comprising a diamond NV center proximal to the heat source, said diamond NV center having a temperature-dependent zero-field splitting of its ground electronic spin state;
applying an optical pulse to polarize the ground electronic spin state;
applying a plurality of microwave pulses to alter the spin population of the spin system;
applying a series of optical pulses to the spin system;
measuring a spin-state-dependent fluorescence rate to detect the spin projection of the electronic ground state of the NV center; and
determining the temperature of the heat source from the spin-state-dependent fluorescence rate.
2. The method of claim 1 , wherein the determined temperature is indicative of a temperature at the micro to nanometer scale.
3. The method of claim 1 , wherein the plurality of microwave pulses comprises a 2π-echo-pulse sequence or its equivalent variations.
4. The method of claim 1 wherein the microwave pulse is detuned from the zero-field splitting by 0 MHz to 500 MHz of the resonant frequency.
5. The method of claim 1 , wherein the evolution time is in the range of 0 μs to 10000 μs.
6. The method of claim 1 , wherein the temperature sensitivity ranges from 10 K/Hz 1/2 to 50 μK/Hz 1/2 .
7. The method of claim 1 , wherein the heat source has a temperature between 100K and 600K.
8. The method of claim 1 , wherein the amount of 13 C impurity in the diamond is 0.0001% to 1.2%.
9. The method of claim 1 , wherein the determining the temperature from the spin-state-dependent fluorescence rate comprises:
determining temperature-dependent zero-field splitting of the NV center; and
determining the temperature based on the temperature-dependent zero-field splitting.