Ahwp05m 980

It mainly comprises two‐photon excitation and visible fluorescence detection, as illustrated in Figure S5, Supporting Information. The intensity of the femtosecond laser source (either a 920 nm (Spark Lasers, ALCOR 920) or a 1036 nm (YSL, Femto YLTM)) was controlled by a 1/2 λ wave plate (Thorlabs, AHWP05M‐980) and a polarizing beam splitter (PBS) cube (Thorlabs, CCM1‐ PBS252). The laser beam was then expanded by lenses (L1 and L2) and reflected to a high‐speed spatial light modulator (SLM, Meadowlark, HSP1920‐1152) at ≈10°. Another 1/2 λ wave plate was used to facilitate the desired polarization of the SLM. L3 and L4 create magnified phase patterns of the SLM at the rear pupil plane of the objective (Nikon, CFI Apo LWD 25X, 1.1 NA, and 2 mm WD). The fluorescence beam was focused by L5 and then captured by an EMCCD (Andor, Life 888, 1024 × 1024 pixels, 13 × 13 µm²).

A Ti:sapphire laser (Chameleon vision II, Coherent) provided ultrashort laser pulses at 900 nm (initial pulse width ~ 100 fs) pre-chirped by an embedded prism array. The beam intensity was controlled by using an achromatic half-wave plate (AHWP05M-980, Thorlabs) and a calcite polarizer (10GL08AR.16, Newport). Dichroic beam splitter (FF705-Di01-25 × 36, Semrock) passed the laser pulses (900 nm/840 nm/880 nm) and reflected signal (509~525 nm for two-photon singal 420~440 nm for label free signal). To couple the laser to the core of DCF, the beam was initially expanded using two achromatic lenses (f = 160 mm, 67-334-INK, Edmund Optics), (f = 30 mm, 49–352-INK, Edmund Optics). The expanded beam was focused by using a microscope objective lens (RMS X10, Thorlabs) and coupled to the core of DCF (see Supplementary Fig. S4). The emission light from a sample passed a band pass filter (FF01-525/45–25, Semrock for two-photon signal and FF01-417/60–25, Semrock for label-free signal) to transmit only signal, and the signal was focused to the photomultiplier (R3788, Hamamatsu) using an achromatic lens (47–633-INK, Edmund Optics).