Method for forming an image of at least one particle, arranged in a sample, using a device comprising: - a light source, which is able to emit a light wave, referred to as the incident wave, at an emission wavelength (λ), along a propagation axis, towards the sample; - an image sensor; - a holder, arranged between the light source and the image sensor, the holder defining a holder plane (Ps), the holder being transparent to the emission wavelength and comprising a lower reflector (25, 55), formed from at least two materials (21, 22) having different refractive indices, at the emission wavelength, the lower reflector extending between the holder plane and the image sensor; - an upper reflector (15, 45), formed from at least two materials having different refractive indices (11, 12), at the emission wavelength, the upper reflector extending between the holder plane (Ps) and the light source, the upper reflector (15, 45) being arranged facing the lower reflector (25, 55), so as to form a resonant optical cavity (9, 9'); - a free space between the upper reflector and the holder; - no image-forming optic being arranged between the sample and the image sensor; the method comprising the following steps: - arranging the sample in the free space; - the light source emitting a light wave, the light wave propagating, through the upper reflector, towards the sample, then undergoing multiple resonant reflections in the resonant cavity resulting in an amplification of the light wave propagating in the optical cavity; - under the effect of the presence of the particle in the sample: ∘ the particle scattering part of the light wave propagating in the resonant cavity, through the holder, in order to form a scattered wave propagating towards the image sensor; ∘ transmitting part of the light wave propagating in the resonant cavity towards the image sensor; - the image sensor acquiring an image, the image comprising a hologram, making it possible at least to locate the particle. - a light source, which is able to emit a light wave, referred to as the incident wave, at an emission wavelength (λ), along a propagation axis, towards the sample; - an image sensor; - a holder, arranged between the light source and the image sensor, the holder defining a holder plane (Ps), the holder being transparent to the emission wavelength and comprising a lower reflector (25, 55), formed from at least two materials (21, 22) having different refractive indices, at the emission wavelength, the lower reflector extending between the holder plane and the image sensor; - an upper reflector (15, 45), formed from at least two materials having different refractive indices (11, 12), at the emission wavelength, the upper reflector extending between the holder plane (Ps) and the light source, the upper reflector (15, 45) being arranged facing the lower reflector (25, 55), so as to form a resonant optical cavity (9, 9'); - a free space between the upper reflector and the holder; - no image-forming optic being arranged between the sample and the image sensor; - arranging the sample in the free space; - the light source emitting a light wave, the light wave propagating, through the upper reflector, towards the sample, then undergoing multiple resonant reflections in the resonant cavity resulting in an amplification of the light wave propagating in the optical cavity; - under the effect of the presence of the particle in the sample: ∘ the particle scattering part of the light wave propagating in the resonant cavity, through the holder, in order to form a scattered wave propagating towards the image sensor; ∘ transmitting part of the light wave propagating in the resonant cavity towards the image sensor; ∘ the particle scattering part of the light wave propagating in the resonant cavity, through the holder, in order to form a scattered wave propagating towards the image sensor; ∘ transmitting part of the light wave propagating in the resonant cavity towards the image sensor; - the image sensor acquiring an image, the image comprising a hologram, making it possible at least to locate the particle.