be operated as an electron spin resonance excitation source and or passively as a detector the stm and ewp probe share the same tip and thus the modulation signal of the tunneling current which was induced by the spin resonance will be coupled into the ewp stm probe in one embodiment of the present invention the input power source and the output signal circuit of the spin resonance microscope are coupled to the resonator through separate ports such that transmitted power is measured by the microscope in an alternative embodiment of the present invention the input power source and the output signal circuit of the spin resonance microscope are coupled to the resonator through the same port such that reflected power is measured by the microscope these two embodiments are not specifically illustrated in fig1 rather the figure simply shows that a coupling kit 14 may be arranged to serve a variety of desired configurations the present design illustrated in fig1 dramatically increases the detection sensitivity since the resonator provides a substantially ideal impedance match between the tunneling and microwave circuits an additional advantage is that the signal derived from the microwave modulation of the tunneling current will be resonantly enhanced by about a factor of q i e from about 10 to 1 000 before being amplified by the low noise microwave amplifier an alternative embodiment is illustrated in.