**4. Effects of number of laser pulses**

The total number of laser pulses delivered to the substrate is related to the scanning speed and laser frequency used while irradiation is taking place [40–42]. Effects of scanning speed on the number of laser pulses delivered to surface of the titanium substrates during laser irradia‐ tion are examined. Similar to power, scanning parameters have a direct effect on the surface topography and oxidation of treated titanium substrates. These effects are monitored using various scanning parameters, while keeping power and frequency constant. **Table 2** dis‐ plays the parameters used.


**Table 2.** Scanning speed and pulse numbers used in surface treating of Ti substrates (pulse width, 35 ns; pulse energy, 0.1 mJ).

Scanning speed and the number of laser pulses are indirectly related. With an increase in scanning speed, the pulse number decreases. This is because with a lower scanning speed, more time is given to the laser to induce a pattern across the surface; hence, more pulses are delivered to the substrates.

#### **4.1. Surface topography analysis**

Similar to power, the effects of different scanning speeds on surface topographic properties of the treated substrates are examined using SEM photography. **Figure 7** displays these results.

**Figure 7.** Surface of treated titanium (A) 50 μm/ms, (B) 200 μm/ms, (C) 400 μm/ms, (D) 500 μm/ms.

As shown in this figure, with an increase in scanning speed, the surface irregularities de‐ crease in size; therefore, fewer topographic changes take place on those samples. This is in agreement with expectations, since **Figure 7(A)** with a scanning speed of 50 μm/ms has a larger number of pulses compared to **Figure 7(B)** with a scanning speed of 500 μm/ms.

The surface profile of these substrates is shown in more detail in **Figure 8**.

**Figure 8.** Surface profile of Ti (A) 50 μm/ms, (B) 200 μm/ms, (C) 400 μm/ms, (D) 500 μm/ms.

**Figure 8(A)** shows how irregularities cover the entire surface of the substrates, as opposed to only along the irradiation zone as shown in **Figure 8(D)**. This agrees with the expectations.

#### **4.2. Biocompatibility assessment**

**4. Effects of number of laser pulses**

**Frequency (kHz)**

**Average power** 

 100 10  167 16.7 100 10  41 4.1 100 10  21 2.1 100 10  17 1.7

**(W)**

plays the parameters used.

364 366High Energy and Short Pulse Lasers

delivered to the substrates.

**4.1. Surface topography analysis**

**Scanning speed** 

**(μm/ms)**

0.1 mJ).

The total number of laser pulses delivered to the substrate is related to the scanning speed and laser frequency used while irradiation is taking place [40–42]. Effects of scanning speed on the number of laser pulses delivered to surface of the titanium substrates during laser irradia‐ tion are examined. Similar to power, scanning parameters have a direct effect on the surface topography and oxidation of treated titanium substrates. These effects are monitored using various scanning parameters, while keeping power and frequency constant. **Table 2** dis‐

**Table 2.** Scanning speed and pulse numbers used in surface treating of Ti substrates (pulse width, 35 ns; pulse energy,

Scanning speed and the number of laser pulses are indirectly related. With an increase in scanning speed, the pulse number decreases. This is because with a lower scanning speed, more time is given to the laser to induce a pattern across the surface; hence, more pulses are

Similar to power, the effects of different scanning speeds on surface topographic properties of the treated substrates are examined using SEM photography. **Figure 7** displays these results.

**Figure 7.** Surface of treated titanium (A) 50 μm/ms, (B) 200 μm/ms, (C) 400 μm/ms, (D) 500 μm/ms.

**Total number of laser pulses Total delivered energy (mJ)** 

To see how influential the number of pulses is on bioactivity enhancement of titanium, a wider range of scanning speeds is used to assess the apatite‐inducing ability of treated titanium substrates. Scanning speeds of 300 and 700 μm/ms are used to treat these substrates in order to more clearly show the differences between the two substrates. All other parameters remain the same (**Table 3**).


**Table 3.** Scanning speed and pulse numbers used in surface treating of Ti substrates (pulse width, 35 ns; pulse energy, 0.1 mJ.

**Figure 9** displays the substrates immersed in SBF for 7 days.

**Figure 9.** SBF‐soaked substrates (A) 300 μm/ms, (B) 700 μm/ms.

As stated, a lower scanning speed delivers a larger number of pulses and therefore affects the surface topographic properties of the titanium more significantly. Additionally, with a larger number of pulses, the average surface temperature of the substrate increases, and therefore, a more ideal condition for the creation of titanium oxide is generated [25, 43]. **Figure 9** dis‐ plays these effects clearly. Considering **Figure 9(A)**, more apatite deposition is observed across the surface as opposed to **Figure 9(B)**, which agrees with the expectations.

The apatite‐inducing ability of these titanium substrates is further analyzed using EDX. **Figure 10** displays the results.

**Figure 10.** EDX analysis (A) 300 μm/ms, (B) 700 μm/ms.

It is evident in **Figure 10** that calcium and phosphorous concentrations detected across the surface are larger for the curve of 300 mm/s. This agrees with observations from **Figures 7** and **8**.

Overall, it was observed that with a larger number of laser pulses, more energy is delivered to the material, and therefore more surface topographic and oxidation changes take place across the surface of the treated substrates.
